Python运维开发：运算符与数据类型（二）
2024-03-19 22:11:21
python对象的相关术语：
python程序中保存的所有数据都是围绕对象这个概念展开的：
- 程序中存储的所有数据都是对象
- 每个对象都有一个身份、一个类型和一个值
例如，school='MaGe Linux'会以'MaGe Linux'创建一个字符串对象，其身份是指向它在内存中所处位置的指针(其在内存中的地址),而school就是引用这个具体位置的名称
- 对象的类型也称对象的类别，用于描述对象的内部表示及它支持的方法和操作
- 创建特定类型的对象时，有时也将该对象称为该类型的实例
- 实例被创建后，其身份和类型就不可改变
如果对象的值是可修改的，则称为可变对象
如果对象的值不可修改，则称为不可变对象
- 如果某个对象包含对其他对象的引用，则将其称为容器
- 大多数对象都拥有大量特有的数据属性和方法
属性：与对象相关的值
方法：被调用时将在对象上执行某些操作的函数
使用点(.)运算符可以访问属性和方法
对象的身份与类型：
python内置函数id()可返回一个对象的身份，即该对象在内存中的位置
- is 运算符用于比较两个对象的身份
- type() 用于返回一个对象的类型
- 对象类型本身也是一个对象，称为对象的类
(1)该对象的定义是唯一的，且对于某类型的所有实例都是相同的
(2)所有类型对象都有一个指定的名称，可用于执行类型检查,如list、dict
示例：
>>> num1 = 5
>>> num2 = 5
>>> num1 == num2 #值比较
True >>> id(num1) #内存中的地址
1568501344
>>> id(num2)
1568501344
>>> num1 is num2 #身份比较
True >>> type(num1) is type(num2) #类型比较
True
运算符
a=10
b=20
一、算数运算：
二、比较运算：
三、赋值运算：
四、逻辑运算：
五、成员运算：
六、身份运算：
七、位运算：
1byte = 8bit
2**8 2**7 2**6 2**5 2**4 2**3 2**2 2**1 2**0
256 128 64 32 16 8 4 2 1
以下实例演示了Python所有位运算符的操作：
#!/usr/bin/python
# -*- coding: UTF-8 -*- a = 60 # 60 = 0011 1100
b = 13 # 13 = 0000 1101
c = 0 c = a & b; # 12 = 0000 1100
print("1 -c 的值为:", c) c = a | b; # 61 = 0011 1101
print("2 -c 的值为:", c) c = a ^ b; # 49 = 0011 0001
print("3 -c 的值为:", c) c = ~a; # -61 = 1100 0011
print("4 -c 的值为:", c) c = a << 2; # 240 = 1111 0000
print("5 -c 的值为:", c) c = a >> 2; # 15 = 0000 1111
print("6 -c 的值为:", c)
八、运算符优先级：
更多内容：猛击这里
数据类型
核心数据类型：
- 数字：int, long(python3.5已经没有), float, complex, bool
- 字符：str, unicode
- 列表：list
- 字典：dict
- 元组：tuple
- 集合：set(可变集合),frozenset(不可变集合)
- 文件：file
数字类型：
python的数字字面量：整数，布尔型，浮点数，复数，所有数字类型均为不可变
int（整型）
在32位机器上，整数的位数为32位，取值范围为-2**31～2**31-1，即-2147483648～2147483647
在64位系统上，整数的位数为64位，取值范围为-2**63～2**63-1，即-9223372036854775808～9223372036854775807
在64位系统上，整数的位数为64位，取值范围为-2**63～2**63-1，即-9223372036854775808～9223372036854775807
bool(布尔型)
真或假
1 或 0
float(浮点型)
数字操作：+ , -, *, /, //, **, %, -x, +x
附上源码：
class int(object):
"""
int(x=0) -> int or long
int(x, base=10) -> int or long Convert a number or string to an integer, or return 0 if no arguments
are given. If x is floating point, the conversion truncates towards zero.
If x is outside the integer range, the function returns a long instead. If x is not a number or if base is given, then x must be a string or
Unicode object representing an integer literal in the given base. The
literal can be preceded by '+' or '-' and be surrounded by whitespace.
The base defaults to 10. Valid bases are 0 and 2-36. Base 0 means to
interpret the base from the string as an integer literal.
>>> int('0b100', base=0)
"""
def bit_length(self):
""" 返回表示该数字的时占用的最少位数 """
"""
int.bit_length() -> int Number of bits necessary to represent self in binary.
>>> bin(37)
'0b100101'
>>> (37).bit_length()
"""
return 0 def conjugate(self, *args, **kwargs): # real signature unknown
""" 返回该复数的共轭复数 """
""" Returns self, the complex conjugate of any int. """
pass def __abs__(self):
""" 返回绝对值 """
""" x.__abs__() <==> abs(x) """
pass def __add__(self, y):
""" x.__add__(y) <==> x+y """
pass def __and__(self, y):
""" x.__and__(y) <==> x&y """
pass def __cmp__(self, y):
""" 比较两个数大小 """
""" x.__cmp__(y) <==> cmp(x,y) """
pass def __coerce__(self, y):
""" 强制生成一个元组 """
""" x.__coerce__(y) <==> coerce(x, y) """
pass def __divmod__(self, y):
""" 相除，得到商和余数组成的元组 """
""" x.__divmod__(y) <==> divmod(x, y) """
pass def __div__(self, y):
""" x.__div__(y) <==> x/y """
pass def __float__(self):
""" 转换为浮点类型 """
""" x.__float__() <==> float(x) """
pass def __floordiv__(self, y):
""" x.__floordiv__(y) <==> x//y """
pass def __format__(self, *args, **kwargs): # real signature unknown
pass def __getattribute__(self, name):
""" x.__getattribute__('name') <==> x.name """
pass def __getnewargs__(self, *args, **kwargs): # real signature unknown
""" 内部调用 __new__方法或创建对象时传入参数使用 """
pass def __hash__(self):
"""如果对象object为哈希表类型，返回对象object的哈希值。哈希值为整数。在字典查找中，哈希值用于快速比较字典的键。两个数值如果相等，则哈希值也相等。"""
""" x.__hash__() <==> hash(x) """
pass def __hex__(self):
""" 返回当前数的 十六进制 表示 """
""" x.__hex__() <==> hex(x) """
pass def __index__(self):
""" 用于切片，数字无意义 """
""" x[y:z] <==> x[y.__index__():z.__index__()] """
pass def __init__(self, x, base=10): # known special case of int.__init__
""" 构造方法，执行 x = 123 或 x = int(10) 时，自动调用，暂时忽略 """
"""
int(x=0) -> int or long
int(x, base=10) -> int or long Convert a number or string to an integer, or return 0 if no arguments
are given. If x is floating point, the conversion truncates towards zero.
If x is outside the integer range, the function returns a long instead. If x is not a number or if base is given, then x must be a string or
Unicode object representing an integer literal in the given base. The
literal can be preceded by '+' or '-' and be surrounded by whitespace.
The base defaults to 10. Valid bases are 0 and 2-36. Base 0 means to
interpret the base from the string as an integer literal.
>>> int('0b100', base=0)
# (copied from class doc)
"""
pass def __int__(self):
""" 转换为整数 """
""" x.__int__() <==> int(x) """
pass def __invert__(self):
""" x.__invert__() <==> ~x """
pass def __long__(self):
""" 转换为长整数 """
""" x.__long__() <==> long(x) """
pass def __lshift__(self, y):
""" x.__lshift__(y) <==> x<<y """
pass def __mod__(self, y):
""" x.__mod__(y) <==> x%y """
pass def __mul__(self, y):
""" x.__mul__(y) <==> x*y """
pass def __neg__(self):
""" x.__neg__() <==> -x """
pass @staticmethod # known case of __new__
def __new__(S, *more):
""" T.__new__(S, ...) -> a new object with type S, a subtype of T """
pass def __nonzero__(self):
""" x.__nonzero__() <==> x != 0 """
pass def __oct__(self):
""" 返回改值的 八进制 表示 """
""" x.__oct__() <==> oct(x) """
pass def __or__(self, y):
""" x.__or__(y) <==> x|y """
pass def __pos__(self):
""" x.__pos__() <==> +x """
pass def __pow__(self, y, z=None):
""" 幂，次方 """
""" x.__pow__(y[, z]) <==> pow(x, y[, z]) """
pass def __radd__(self, y):
""" x.__radd__(y) <==> y+x """
pass def __rand__(self, y):
""" x.__rand__(y) <==> y&x """
pass def __rdivmod__(self, y):
""" x.__rdivmod__(y) <==> divmod(y, x) """
pass def __rdiv__(self, y):
""" x.__rdiv__(y) <==> y/x """
pass def __repr__(self):
"""转化为解释器可读取的形式 """
""" x.__repr__() <==> repr(x) """
pass def __str__(self):
"""转换为人阅读的形式，如果没有适于人阅读的解释形式的话，则返回解释器课阅读的形式"""
""" x.__str__() <==> str(x) """
pass def __rfloordiv__(self, y):
""" x.__rfloordiv__(y) <==> y//x """
pass def __rlshift__(self, y):
""" x.__rlshift__(y) <==> y<<x """
pass def __rmod__(self, y):
""" x.__rmod__(y) <==> y%x """
pass def __rmul__(self, y):
""" x.__rmul__(y) <==> y*x """
pass def __ror__(self, y):
""" x.__ror__(y) <==> y|x """
pass def __rpow__(self, x, z=None):
""" y.__rpow__(x[, z]) <==> pow(x, y[, z]) """
pass def __rrshift__(self, y):
""" x.__rrshift__(y) <==> y>>x """
pass def __rshift__(self, y):
""" x.__rshift__(y) <==> x>>y """
pass def __rsub__(self, y):
""" x.__rsub__(y) <==> y-x """
pass def __rtruediv__(self, y):
""" x.__rtruediv__(y) <==> y/x """
pass def __rxor__(self, y):
""" x.__rxor__(y) <==> y^x """
pass def __sub__(self, y):
""" x.__sub__(y) <==> x-y """
pass def __truediv__(self, y):
""" x.__truediv__(y) <==> x/y """
pass def __trunc__(self, *args, **kwargs):
""" 返回数值被截取为整形的值，在整形中无意义 """
pass def __xor__(self, y):
""" x.__xor__(y) <==> x^y """
pass denominator = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
""" 分母 = 1 """
"""the denominator of a rational number in lowest terms""" imag = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
""" 虚数，无意义 """
"""the imaginary part of a complex number""" numerator = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
""" 分子 = 数字大小 """
"""the numerator of a rational number in lowest terms""" real = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
""" 实属，无意义 """
"""the real part of a complex number""" int
序列类型：
序列表示索引为非负整数的有序对象集合，包括字符串、列表和元组
字符串是字符的
列表和元组是任意python对象的序列
字符和元组属于不可变序列，而列表则支持插入、删除和替换元素等
所有序列都支持迭代
序列操作总结：(当然元组是不可变对象,对元素的操作是不支持的,当然了有嵌套列表字典是可以操作的)
- s + r 连接
- s * n 重复s的n次复制
- v1,v2...vn = s 变量解包(unpack)
- s[i] 索引
- s[i:j] 切片
- s[i:j:stride] 扩展切片
- x in s,x not in s 成员关系
- for x in s: 迭代
- all(s) 如果s中的所有项都为True，则返回True
- any(s) 如果s中的任意项为True，则返回True
- len(s) 长度,元素个数
- min(s) s中的最小项
- max(s) s中的最大项
- sum(s [,initial]) 具有可选初始值的项的和
- del s[i] 删除一个元素
- del s[i:j] 删除一个切片
- del s[i:j:stride] 删除一个扩展切片
字符类型：不可变对象
字符串字面量：把文本放入单引号、双引号或三引号中，python2.x默认不是国际字符集unicode，需要unicode定义时加上u,python3无需加
>>> str1 = u'hello world' # python2.x
>>> type(str1)
<type 'unicode'> >>> str1 = u'hello world' # python3.x
>>> type(str1)
<class 'str'>
文档字串：模块、类或函数的第一条语句是一个字符的话，该字符串就成为文档字符串，可以使用__doc__属性引用
>>> def print_name(): # python 2.x
... 'test function'
... print('hello world')
...
>>> print_name.__doc__
'test function'
适用于字符串常用方法：
str.capitalize() 将字符串的首字母变大写
str.title() 将字符串中的每个单词的首字母大写
str.upper() 将字符串变成大写
str.lower() 将字符串变成小写
str.index() 找出索引对应的字符串
str.find() 同上
str.count() 找出字符串中元素出现的次数
str.format() 也是格式化的一种
str.center() 以什么字符从字符串两边填充
str.join() 以str为分隔符连接字符串
str.split() 以什么为分隔符分隔字符串
str.strip() 将字符串两边中的空格去掉
str.replace() 查找替换
str.isupper() 判断是否为大写
str.islower() 判断是否为小写
str.isalnum() 判断是否是字母数字
str.isalpha() 判断是否是字母下划线
str.isdigit() 判断是否是数字
str.isspace() 判断是否为空
str.startswith() 找出以什么为开头的字符元素
str.endswith() 找出以什么为结尾的字符元素
附上源码：
class str(basestring):
"""
str(object='') -> string Return a nice string representation of the object.
If the argument is a string, the return value is the same object.
"""
def capitalize(self):
""" 首字母变大写 """
"""
S.capitalize() -> string Return a copy of the string S with only its first character
capitalized.
"""
return "" def center(self, width, fillchar=None):
""" 内容居中，width：总长度；fillchar：空白处填充内容，默认无 """
"""
S.center(width[, fillchar]) -> string Return S centered in a string of length width. Padding is
done using the specified fill character (default is a space)
"""
return "" def count(self, sub, start=None, end=None):
""" 子序列个数 """
"""
S.count(sub[, start[, end]]) -> int Return the number of non-overlapping occurrences of substring sub in
string S[start:end]. Optional arguments start and end are interpreted
as in slice notation.
"""
return 0 def decode(self, encoding=None, errors=None):
""" 解码 """
"""
S.decode([encoding[,errors]]) -> object Decodes S using the codec registered for encoding. encoding defaults
to the default encoding. errors may be given to set a different error
handling scheme. Default is 'strict' meaning that encoding errors raise
a UnicodeDecodeError. Other possible values are 'ignore' and 'replace'
as well as any other name registered with codecs.register_error that is
able to handle UnicodeDecodeErrors.
"""
return object() def encode(self, encoding=None, errors=None):
""" 编码，针对unicode """
"""
S.encode([encoding[,errors]]) -> object Encodes S using the codec registered for encoding. encoding defaults
to the default encoding. errors may be given to set a different error
handling scheme. Default is 'strict' meaning that encoding errors raise
a UnicodeEncodeError. Other possible values are 'ignore', 'replace' and
'xmlcharrefreplace' as well as any other name registered with
codecs.register_error that is able to handle UnicodeEncodeErrors.
"""
return object() def endswith(self, suffix, start=None, end=None):
""" 是否以 xxx 结束 """
"""
S.endswith(suffix[, start[, end]]) -> bool Return True if S ends with the specified suffix, False otherwise.
With optional start, test S beginning at that position.
With optional end, stop comparing S at that position.
suffix can also be a tuple of strings to try.
"""
return False def expandtabs(self, tabsize=None):
""" 将tab转换成空格，默认一个tab转换成8个空格 """
"""
S.expandtabs([tabsize]) -> string Return a copy of S where all tab characters are expanded using spaces.
If tabsize is not given, a tab size of 8 characters is assumed.
"""
return "" def find(self, sub, start=None, end=None):
""" 寻找子序列位置，如果没找到，返回 -1 """
"""
S.find(sub [,start [,end]]) -> int Return the lowest index in S where substring sub is found,
such that sub is contained within S[start:end]. Optional
arguments start and end are interpreted as in slice notation. Return -1 on failure.
"""
return 0 def format(*args, **kwargs): # known special case of str.format
""" 字符串格式化，动态参数，将函数式编程时细说 """
"""
S.format(*args, **kwargs) -> string Return a formatted version of S, using substitutions from args and kwargs.
The substitutions are identified by braces ('{' and '}').
"""
pass def index(self, sub, start=None, end=None):
""" 子序列位置，如果没找到，报错 """
S.index(sub [,start [,end]]) -> int Like S.find() but raise ValueError when the substring is not found.
"""
return 0 def isalnum(self):
""" 是否是字母和数字 """
"""
S.isalnum() -> bool Return True if all characters in S are alphanumeric
and there is at least one character in S, False otherwise.
"""
return False def isalpha(self):
""" 是否是字母 """
"""
S.isalpha() -> bool Return True if all characters in S are alphabetic
and there is at least one character in S, False otherwise.
"""
return False def isdigit(self):
""" 是否是数字 """
"""
S.isdigit() -> bool Return True if all characters in S are digits
and there is at least one character in S, False otherwise.
"""
return False def islower(self):
""" 是否小写 """
"""
S.islower() -> bool Return True if all cased characters in S are lowercase and there is
at least one cased character in S, False otherwise.
"""
return False def isspace(self):
"""
S.isspace() -> bool Return True if all characters in S are whitespace
and there is at least one character in S, False otherwise.
"""
return False def istitle(self):
"""
S.istitle() -> bool Return True if S is a titlecased string and there is at least one
character in S, i.e. uppercase characters may only follow uncased
characters and lowercase characters only cased ones. Return False
otherwise.
"""
return False def isupper(self):
"""
S.isupper() -> bool Return True if all cased characters in S are uppercase and there is
at least one cased character in S, False otherwise.
"""
return False def join(self, iterable):
""" 连接 """
"""
S.join(iterable) -> string Return a string which is the concatenation of the strings in the
iterable. The separator between elements is S.
"""
return "" def ljust(self, width, fillchar=None):
""" 内容左对齐，右侧填充 """
"""
S.ljust(width[, fillchar]) -> string Return S left-justified in a string of length width. Padding is
done using the specified fill character (default is a space).
"""
return "" def lower(self):
""" 变小写 """
"""
S.lower() -> string Return a copy of the string S converted to lowercase.
"""
return "" def lstrip(self, chars=None):
""" 移除左侧空白 """
"""
S.lstrip([chars]) -> string or unicode Return a copy of the string S with leading whitespace removed.
If chars is given and not None, remove characters in chars instead.
If chars is unicode, S will be converted to unicode before stripping
"""
return "" def partition(self, sep):
""" 分割，前，中，后三部分 """
"""
S.partition(sep) -> (head, sep, tail) Search for the separator sep in S, and return the part before it,
the separator itself, and the part after it. If the separator is not
found, return S and two empty strings.
"""
pass def replace(self, old, new, count=None):
""" 替换 """
"""
S.replace(old, new[, count]) -> string Return a copy of string S with all occurrences of substring
old replaced by new. If the optional argument count is
given, only the first count occurrences are replaced.
"""
return "" def rfind(self, sub, start=None, end=None):
"""
S.rfind(sub [,start [,end]]) -> int Return the highest index in S where substring sub is found,
such that sub is contained within S[start:end]. Optional
arguments start and end are interpreted as in slice notation. Return -1 on failure.
"""
return 0 def rindex(self, sub, start=None, end=None):
"""
S.rindex(sub [,start [,end]]) -> int Like S.rfind() but raise ValueError when the substring is not found.
"""
return 0 def rjust(self, width, fillchar=None):
"""
S.rjust(width[, fillchar]) -> string Return S right-justified in a string of length width. Padding is
done using the specified fill character (default is a space)
"""
return "" def rpartition(self, sep):
"""
S.rpartition(sep) -> (head, sep, tail) Search for the separator sep in S, starting at the end of S, and return
the part before it, the separator itself, and the part after it. If the
separator is not found, return two empty strings and S.
"""
pass def rsplit(self, sep=None, maxsplit=None):
"""
S.rsplit([sep [,maxsplit]]) -> list of strings Return a list of the words in the string S, using sep as the
delimiter string, starting at the end of the string and working
to the front. If maxsplit is given, at most maxsplit splits are
done. If sep is not specified or is None, any whitespace string
is a separator.
"""
return [] def rstrip(self, chars=None):
"""
S.rstrip([chars]) -> string or unicode Return a copy of the string S with trailing whitespace removed.
If chars is given and not None, remove characters in chars instead.
If chars is unicode, S will be converted to unicode before stripping
"""
return "" def split(self, sep=None, maxsplit=None):
""" 分割， maxsplit最多分割几次 """
"""
S.split([sep [,maxsplit]]) -> list of strings Return a list of the words in the string S, using sep as the
delimiter string. If maxsplit is given, at most maxsplit
splits are done. If sep is not specified or is None, any
whitespace string is a separator and empty strings are removed
from the result.
"""
return [] def splitlines(self, keepends=False):
""" 根据换行分割 """
"""
S.splitlines(keepends=False) -> list of strings Return a list of the lines in S, breaking at line boundaries.
Line breaks are not included in the resulting list unless keepends
is given and true.
"""
return [] def startswith(self, prefix, start=None, end=None):
""" 是否起始 """
"""
S.startswith(prefix[, start[, end]]) -> bool Return True if S starts with the specified prefix, False otherwise.
With optional start, test S beginning at that position.
With optional end, stop comparing S at that position.
prefix can also be a tuple of strings to try.
"""
return False def strip(self, chars=None):
""" 移除两段空白 """
"""
S.strip([chars]) -> string or unicode Return a copy of the string S with leading and trailing
whitespace removed.
If chars is given and not None, remove characters in chars instead.
If chars is unicode, S will be converted to unicode before stripping
"""
return "" def swapcase(self):
""" 大写变小写，小写变大写 """
"""
S.swapcase() -> string Return a copy of the string S with uppercase characters
converted to lowercase and vice versa.
"""
return "" def title(self):
"""
S.title() -> string Return a titlecased version of S, i.e. words start with uppercase
characters, all remaining cased characters have lowercase.
"""
return "" def translate(self, table, deletechars=None):
"""
转换，需要先做一个对应表，最后一个表示删除字符集合
intab = "aeiou"
outtab = ""
trantab = maketrans(intab, outtab)
str = "this is string example....wow!!!"
print str.translate(trantab, 'xm')
""" """
S.translate(table [,deletechars]) -> string Return a copy of the string S, where all characters occurring
in the optional argument deletechars are removed, and the
remaining characters have been mapped through the given
translation table, which must be a string of length 256 or None.
If the table argument is None, no translation is applied and
the operation simply removes the characters in deletechars.
"""
return "" def upper(self):
"""
S.upper() -> string Return a copy of the string S converted to uppercase.
"""
return "" def zfill(self, width):
"""方法返回指定长度的字符串，原字符串右对齐，前面填充0。"""
"""
S.zfill(width) -> string Pad a numeric string S with zeros on the left, to fill a field
of the specified width. The string S is never truncated.
"""
return "" def _formatter_field_name_split(self, *args, **kwargs): # real signature unknown
pass def _formatter_parser(self, *args, **kwargs): # real signature unknown
pass def __add__(self, y):
""" x.__add__(y) <==> x+y """
pass def __contains__(self, y):
""" x.__contains__(y) <==> y in x """
pass def __eq__(self, y):
""" x.__eq__(y) <==> x==y """
pass def __format__(self, format_spec):
"""
S.__format__(format_spec) -> string Return a formatted version of S as described by format_spec.
"""
return "" def __getattribute__(self, name):
""" x.__getattribute__('name') <==> x.name """
pass def __getitem__(self, y):
""" x.__getitem__(y) <==> x[y] """
pass def __getnewargs__(self, *args, **kwargs): # real signature unknown
pass def __getslice__(self, i, j):
"""
x.__getslice__(i, j) <==> x[i:j] Use of negative indices is not supported.
"""
pass def __ge__(self, y):
""" x.__ge__(y) <==> x>=y """
pass def __gt__(self, y):
""" x.__gt__(y) <==> x>y """
pass def __hash__(self):
""" x.__hash__() <==> hash(x) """
pass def __init__(self, string=''): # known special case of str.__init__
"""
str(object='') -> string Return a nice string representation of the object.
If the argument is a string, the return value is the same object.
# (copied from class doc)
"""
pass def __len__(self):
""" x.__len__() <==> len(x) """
pass def __le__(self, y):
""" x.__le__(y) <==> x<=y """
pass def __lt__(self, y):
""" x.__lt__(y) <==> x<y """
pass def __mod__(self, y):
""" x.__mod__(y) <==> x%y """
pass def __mul__(self, n):
""" x.__mul__(n) <==> x*n """
pass @staticmethod # known case of __new__
def __new__(S, *more):
""" T.__new__(S, ...) -> a new object with type S, a subtype of T """
pass def __ne__(self, y):
""" x.__ne__(y) <==> x!=y """
pass def __repr__(self):
""" x.__repr__() <==> repr(x) """
pass def __rmod__(self, y):
""" x.__rmod__(y) <==> y%x """
pass def __rmul__(self, n):
""" x.__rmul__(n) <==> n*x """
pass def __sizeof__(self):
""" S.__sizeof__() -> size of S in memory, in bytes """
pass def __str__(self):
""" x.__str__() <==> str(x) """
pass
列表类型：可变对象
表达式符号：[]
创建列表：
name_list = ['alex', 'seven', 'eric']
或
name_list ＝ list(['alex', 'seven', 'eric'])
容器类型
任意对象的有序集合，通过索引访问其中的元素，可变对象
异构混合类型，可以任意嵌套其它类型
支持在原处修改：
修改指定的索引元素，修改指定的分片，删除语句，类的内置方法
适用于列表常用方法：
list.insert() 在列表中指定索引位置前插入元素
list.append() 在列表尾部插入
list.remove() 删除指定的元素
list.pop() 没有指定索引，则弹出最后一个元素，返回的结果是弹出的索引对应的元素
list.copy() 浅复制,只会复制第一层,如果有嵌套序列则不会复制,如果需要复制则要导入copy模块
list.extend() 把另外一个列表合并，并不是追加
list.index() 列表中元素出现的索引位置
list.count() 统计列表中元素的次数
list.reverse() 进行逆序
list.sort() 进行排序,python3无法把数字和字符串一起排序
l1 + l2 : 合并两个列表，返回一个新的列表，不会修改原列表
l1 * N : 把l1重复N次，返回一个新列表
附上源码：
class list(object):
"""
list() -> new empty list
list(iterable) -> new list initialized from iterable's items
"""
def append(self, p_object): # real signature unknown; restored from __doc__
""" L.append(object) -- append object to end """
pass def count(self, value): # real signature unknown; restored from __doc__
""" L.count(value) -> integer -- return number of occurrences of value """
return 0 def extend(self, iterable): # real signature unknown; restored from __doc__
""" L.extend(iterable) -- extend list by appending elements from the iterable """
pass def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__
"""
L.index(value, [start, [stop]]) -> integer -- return first index of value.
Raises ValueError if the value is not present.
"""
return 0 def insert(self, index, p_object): # real signature unknown; restored from __doc__
""" L.insert(index, object) -- insert object before index """
pass def pop(self, index=None): # real signature unknown; restored from __doc__
"""
L.pop([index]) -> item -- remove and return item at index (default last).
Raises IndexError if list is empty or index is out of range.
"""
pass def remove(self, value): # real signature unknown; restored from __doc__
"""
L.remove(value) -- remove first occurrence of value.
Raises ValueError if the value is not present.
"""
pass def reverse(self): # real signature unknown; restored from __doc__
""" L.reverse() -- reverse *IN PLACE* """
pass def sort(self, cmp=None, key=None, reverse=False): # real signature unknown; restored from __doc__
"""
L.sort(cmp=None, key=None, reverse=False) -- stable sort *IN PLACE*;
cmp(x, y) -> -1, 0, 1
"""
pass def __add__(self, y): # real signature unknown; restored from __doc__
""" x.__add__(y) <==> x+y """
pass def __contains__(self, y): # real signature unknown; restored from __doc__
""" x.__contains__(y) <==> y in x """
pass def __delitem__(self, y): # real signature unknown; restored from __doc__
""" x.__delitem__(y) <==> del x[y] """
pass def __delslice__(self, i, j): # real signature unknown; restored from __doc__
"""
x.__delslice__(i, j) <==> del x[i:j] Use of negative indices is not supported.
"""
pass def __eq__(self, y): # real signature unknown; restored from __doc__
""" x.__eq__(y) <==> x==y """
pass def __getattribute__(self, name): # real signature unknown; restored from __doc__
""" x.__getattribute__('name') <==> x.name """
pass def __getitem__(self, y): # real signature unknown; restored from __doc__
""" x.__getitem__(y) <==> x[y] """
pass def __getslice__(self, i, j): # real signature unknown; restored from __doc__
"""
x.__getslice__(i, j) <==> x[i:j] Use of negative indices is not supported.
"""
pass def __ge__(self, y): # real signature unknown; restored from __doc__
""" x.__ge__(y) <==> x>=y """
pass def __gt__(self, y): # real signature unknown; restored from __doc__
""" x.__gt__(y) <==> x>y """
pass def __iadd__(self, y): # real signature unknown; restored from __doc__
""" x.__iadd__(y) <==> x+=y """
pass def __imul__(self, y): # real signature unknown; restored from __doc__
""" x.__imul__(y) <==> x*=y """
pass def __init__(self, seq=()): # known special case of list.__init__
"""
list() -> new empty list
list(iterable) -> new list initialized from iterable's items
# (copied from class doc)
"""
pass def __iter__(self): # real signature unknown; restored from __doc__
""" x.__iter__() <==> iter(x) """
pass def __len__(self): # real signature unknown; restored from __doc__
""" x.__len__() <==> len(x) """
pass def __le__(self, y): # real signature unknown; restored from __doc__
""" x.__le__(y) <==> x<=y """
pass def __lt__(self, y): # real signature unknown; restored from __doc__
""" x.__lt__(y) <==> x<y """
pass def __mul__(self, n): # real signature unknown; restored from __doc__
""" x.__mul__(n) <==> x*n """
pass @staticmethod # known case of __new__
def __new__(S, *more): # real signature unknown; restored from __doc__
""" T.__new__(S, ...) -> a new object with type S, a subtype of T """
pass def __ne__(self, y): # real signature unknown; restored from __doc__
""" x.__ne__(y) <==> x!=y """
pass def __repr__(self): # real signature unknown; restored from __doc__
""" x.__repr__() <==> repr(x) """
pass def __reversed__(self): # real signature unknown; restored from __doc__
""" L.__reversed__() -- return a reverse iterator over the list """
pass def __rmul__(self, n): # real signature unknown; restored from __doc__
""" x.__rmul__(n) <==> n*x """
pass def __setitem__(self, i, y): # real signature unknown; restored from __doc__
""" x.__setitem__(i, y) <==> x[i]=y """
pass def __setslice__(self, i, j, y): # real signature unknown; restored from __doc__
"""
x.__setslice__(i, j, y) <==> x[i:j]=y Use of negative indices is not supported.
"""
pass def __sizeof__(self): # real signature unknown; restored from __doc__
""" L.__sizeof__() -- size of L in memory, in bytes """
pass __hash__ = None
#通过索引来修改元素
#通过索引来修改元素
>>> print(l2)
[1, 2, 3, 4, 5] >>> l2[1] = 32 >>> print(l2)
[1, 32, 3, 4, 5] >>> l2[3] = 'xyz' >>> print(l2)
[1, 32, 3, 'xyz', 5] >>> print(l1)
[1, 2, 3] >>> l1[1:] = ['m','n','r'] >>> print(l1)
[1,'m','n','r']
#通过分片进行删除
>>> l2[1:3]
[32, 3] >>> l2[1:3] = [] >>> print(l2)
[1, 'xyz', 5]
#通过内置的函数进行删除
>>> del(l2[1:]) >>> print(l2)
[1]
#通过列表类中的方法进行增删改
>>> l3 = [1,2,3,4,5,6] >>> l3.append(77) >>> print(l3)
[1, 2, 3, 4, 5, 6, 77] >>> l4 = ['x','y','z'] >>> l3.append(l4) >>> print(l3)
[1, 2, 3, 4, 5, 6, 77, ['x', 'y', 'z']]
#变量解包
>>> l1,l2 = [[1,'x','y'],[2,'z','r']] >>> print(l1)
[1, 'x', 'y'] >>> type(l1) >>> print(l2)
[2, 'z', 'r']
#找到列表中的元素并修改
tomcat@node:~/scripts$ cat b.py
name = [1,2,3,4,5,1,5,6]
if 1 in name:
num_of_ele = name.count(1)
position_of_ele = name.index(1)
name[position_of_ele] = 888
print(name) tomcat@node:~/scripts$ python b.py
[888, 2, 3, 4, 5, 1, 5, 6]
#找到列表中的元素并批量修改
tomcat@node:~/scripts$ cat b.py
name = [1,2,3,4,5,1,5,6] for i in range(name.count(1)):
ele_index = name.index(1)
name[ele_index] = 8888888
print(name)
tomcat@node:~/scripts$ python b.py
[8888888, 2, 3, 4, 5, 8888888, 5, 6]
元组类型：不可变对象
表达式符号：()
创建元组：
ages = (11, 22, 33, 44, 55)
或
ages = tuple((11, 22, 33, 44, 55))
容器类型
任意对象的有序集合，通过索引访问其中的元素，不可变对象
异构混合类型，可以任意嵌套其它类型
虽然元组本身不可变，但如果元组内嵌套了可变类型的元素，那么此类元素的修改不会返回新元组
(): 空元组
(1,): 单个元组需要尾部加上逗号，如果元素是数字没有加逗号则不是元组
(1,2): 多元素元组
1,2,3,4: 在定义变量时没有加上小括号，默认是元组，最好不建议使用
适用于元组常用方法：
tuple.count() 统计元组中元素的个数
tuple.index() 找出元组中元素的索引位置
#在没有嵌套的情况，元组是不可变对象，但是在嵌套了列表，列表是可变的
>>> t5 = ('x',[1,2,3,4])
>>> print t5
('x', [1, 2, 3, 4])
>>> t5[1].pop()
4
>>> print(t5)
('x', [1, 2, 3])
#元组解包
>>> t1,t2 = ((1,2,3,4,5,'xy'),('s','y','w'))
>>> print(t1)
(1, 2, 3, 4, 5, 'xy')
>>> type(t1)
tuple
>>> print(t2)
('s', 'y', 'w')
字典类型：dict 可变对象
表达式符号：{}
创建字典：
person = {"name": "tomcat", 'age': 18}
或
person = dict({"name": "tomcat", 'age': 18})
字典在其他编程语言中又称作关联数组或散列表
通过键(key)实现元素存取，无序的，可变类型容器，长度可变，异构，嵌套
{}: 空字典
{'x':32,'y':[1,2,3,4]}
两种遍历字典方法：
第一种：
for k,v in dict.items():
print(k,v) 第二种：高效
for key in dict:
print(key,dict[key])
适用于字典常用方法：
dict.get(key) 取得某个key的value
dict.has_key(key) 判断字典是否有这个key,在python3中已经废除,使用in 判断
dict.keys() 返回所有的key为一个列表
dict.values() 返回所有的value为一个列表
dict.items() 将字典的键值拆成元组，全部元组组成一个列表
dict.pop(key) 弹出某个key-value
dict.popitem() 随机弹出key-value
dict.clear() 清除字典中所有元素
dict.copy() 字典复制，d2 = d1.copy(),是浅复制,如果深复制需要copy模块
dict.fromkeys(S) 生成一个新字典
dict.update(key) 将一个字典合并到当前字典中
dict.iteritems() 生成key-value迭代器，可以用next()取下个key-value
dict.iterkeys() 生成key迭代器
dict.itervalues() 生成values迭代器
附上源码：
class dict(object):
"""
dict() -> new empty dictionary
dict(mapping) -> new dictionary initialized from a mapping object's
(key, value) pairs
dict(iterable) -> new dictionary initialized as if via:
d = {}
for k, v in iterable:
d[k] = v
dict(**kwargs) -> new dictionary initialized with the name=value pairs
in the keyword argument list. For example: dict(one=1, two=2)
""" def clear(self): # real signature unknown; restored from __doc__
""" 清除内容 """
""" D.clear() -> None. Remove all items from D. """
pass def copy(self): # real signature unknown; restored from __doc__
""" 浅拷贝 """
""" D.copy() -> a shallow copy of D """
pass @staticmethod # known case
def fromkeys(S, v=None): # real signature unknown; restored from __doc__
"""
dict.fromkeys(S[,v]) -> New dict with keys from S and values equal to v.
v defaults to None.
"""
pass def get(self, k, d=None): # real signature unknown; restored from __doc__
""" 根据key获取值，d是默认值 """
""" D.get(k[,d]) -> D[k] if k in D, else d. d defaults to None. """
pass def has_key(self, k): # real signature unknown; restored from __doc__
""" 是否有key """
""" D.has_key(k) -> True if D has a key k, else False """
return False def items(self): # real signature unknown; restored from __doc__
""" 所有项的列表形式 """
""" D.items() -> list of D's (key, value) pairs, as 2-tuples """
return [] def iteritems(self): # real signature unknown; restored from __doc__
""" 项可迭代 """
""" D.iteritems() -> an iterator over the (key, value) items of D """
pass def iterkeys(self): # real signature unknown; restored from __doc__
""" key可迭代 """
""" D.iterkeys() -> an iterator over the keys of D """
pass def itervalues(self): # real signature unknown; restored from __doc__
""" value可迭代 """
""" D.itervalues() -> an iterator over the values of D """
pass def keys(self): # real signature unknown; restored from __doc__
""" 所有的key列表 """
""" D.keys() -> list of D's keys """
return [] def pop(self, k, d=None): # real signature unknown; restored from __doc__
""" 获取并在字典中移除 """
"""
D.pop(k[,d]) -> v, remove specified key and return the corresponding value.
If key is not found, d is returned if given, otherwise KeyError is raised
"""
pass def popitem(self): # real signature unknown; restored from __doc__
""" 获取并在字典中移除 """
"""
D.popitem() -> (k, v), remove and return some (key, value) pair as a
2-tuple; but raise KeyError if D is empty.
"""
pass def setdefault(self, k, d=None): # real signature unknown; restored from __doc__
""" 如果key不存在，则创建，如果存在，则返回已存在的值且不修改 """
""" D.setdefault(k[,d]) -> D.get(k,d), also set D[k]=d if k not in D """
pass def update(self, E=None, **F): # known special case of dict.update
""" 更新
{'name':'alex', 'age': 18000}
[('name','sbsbsb'),]
"""
"""
D.update([E, ]**F) -> None. Update D from dict/iterable E and F.
If E present and has a .keys() method, does: for k in E: D[k] = E[k]
If E present and lacks .keys() method, does: for (k, v) in E: D[k] = v
In either case, this is followed by: for k in F: D[k] = F[k]
"""
pass def values(self): # real signature unknown; restored from __doc__
""" 所有的值 """
""" D.values() -> list of D's values """
return [] def viewitems(self): # real signature unknown; restored from __doc__
""" 所有项，只是将内容保存至view对象中 """
""" D.viewitems() -> a set-like object providing a view on D's items """
pass def viewkeys(self): # real signature unknown; restored from __doc__
""" D.viewkeys() -> a set-like object providing a view on D's keys """
pass def viewvalues(self): # real signature unknown; restored from __doc__
""" D.viewvalues() -> an object providing a view on D's values """
pass def __cmp__(self, y): # real signature unknown; restored from __doc__
""" x.__cmp__(y) <==> cmp(x,y) """
pass def __contains__(self, k): # real signature unknown; restored from __doc__
""" D.__contains__(k) -> True if D has a key k, else False """
return False def __delitem__(self, y): # real signature unknown; restored from __doc__
""" x.__delitem__(y) <==> del x[y] """
pass def __eq__(self, y): # real signature unknown; restored from __doc__
""" x.__eq__(y) <==> x==y """
pass def __getattribute__(self, name): # real signature unknown; restored from __doc__
""" x.__getattribute__('name') <==> x.name """
pass def __getitem__(self, y): # real signature unknown; restored from __doc__
""" x.__getitem__(y) <==> x[y] """
pass def __ge__(self, y): # real signature unknown; restored from __doc__
""" x.__ge__(y) <==> x>=y """
pass def __gt__(self, y): # real signature unknown; restored from __doc__
""" x.__gt__(y) <==> x>y """
pass def __init__(self, seq=None, **kwargs): # known special case of dict.__init__
"""
dict() -> new empty dictionary
dict(mapping) -> new dictionary initialized from a mapping object's
(key, value) pairs
dict(iterable) -> new dictionary initialized as if via:
d = {}
for k, v in iterable:
d[k] = v
dict(**kwargs) -> new dictionary initialized with the name=value pairs
in the keyword argument list. For example: dict(one=1, two=2)
# (copied from class doc)
"""
pass def __iter__(self): # real signature unknown; restored from __doc__
""" x.__iter__() <==> iter(x) """
pass def __len__(self): # real signature unknown; restored from __doc__
""" x.__len__() <==> len(x) """
pass def __le__(self, y): # real signature unknown; restored from __doc__
""" x.__le__(y) <==> x<=y """
pass def __lt__(self, y): # real signature unknown; restored from __doc__
""" x.__lt__(y) <==> x<y """
pass @staticmethod # known case of __new__
def __new__(S, *more): # real signature unknown; restored from __doc__
""" T.__new__(S, ...) -> a new object with type S, a subtype of T """
pass def __ne__(self, y): # real signature unknown; restored from __doc__
""" x.__ne__(y) <==> x!=y """
pass def __repr__(self): # real signature unknown; restored from __doc__
""" x.__repr__() <==> repr(x) """
pass def __setitem__(self, i, y): # real signature unknown; restored from __doc__
""" x.__setitem__(i, y) <==> x[i]=y """
pass def __sizeof__(self): # real signature unknown; restored from __doc__
""" D.__sizeof__() -> size of D in memory, in bytes """
pass __hash__ = None dict
#字典也支持索引的方式获取,只不过key是他的索引了
>>> d1 = {'x':32,'y':[1,2,3,4]}
>>> d1['x']
32
>>> d1['y']
[1, 2, 3, 4]
>>> d1['y'][3:]
[4]
>>> len(d1)
2
#变量解包1
>>> d1.items()
[('y', [1, 2, 3, 4]), ('x', 32)] >>> t1,t2 = d1.items() >>> print(t1)
('y', [1, 2, 3, 4]) >>> print(t2)
('x', 32)
#变量解包2
>>> d3,d4 = {'x':32,'y':80}
>>> print(d3)
y
>>> print(d4)
x
#合并字典，但是在有相同的key时会覆盖原有的key的值
>>> d1 = {'x':1,'y':2}
>>> d2 = {'m':21,'n':76,'y':44}
>>> d1.update(d2)
>>> print(d1)
{'y': 44, 'x': 1, 'm': 21, 'n': 76}
集合类型：set()可变对象,frozenset()不可变对象
表达式符号：{}
创建集合：
s = {"tom","cat","name","error"}
或
s = set({"tom","cat","name","error"})
集合是一组无序排序的可哈希hash的值,不重复
支持集合关系测试:
支持成员关系测试：in , not in
支持迭代
不支持：索引、元素获取、切片
{"a",123,"b"}或者set()空集合
没有特定语法格式，只能通过工厂函数创建set，像字符串则直接创建即可
set集合必须中的元素必须是可迭代对象,所有元素不会重复,不像list列表是可以重复
集合运算符：
s | t s和t的并集
s & t s和t的交集
s - t 求差集
s ^ t 求对称差集
len(s) 集合中项数
max(s) 最大值
min(s) 最小值
适用于可变集合常用方法：
s.add(item) 将item添加到s中。如果item已经在s中，则无任何效果
s.remove(item) 从s中删除item。如果item不是s的成员，则引发KeyError异常
s.discard(item) 从s中删除item.如果item不是s的成员，则无任何效果
s.pop() 随机删除一个任意集合元素，并将其从s删除,如果有变量接收则会接收到删除到的那个元素
s.clear() 删除s中的所有元素
s.copy() 浅复制
s.update(t) 将t中的所有元素添加到s中。t可以是另一个集合、一个序列或者支持迭代的任意对象 s.union(t) 求并集。返回所有在s和t中的元素
s.intersection(t) 求交集。返回所有同时在s和t中的都有的元素
s.intersection_update(t) 计算s与t的交集，并将结果放入s
s.difference(t) 求差集。返回所有在set中，但不在t中的元素
s.difference_update(t) 从s中删除同时也在t中的所有元素
s.symmetric_difference(t) 求对称差集。返回所有s中没有t中的元素和t中没有s中的元素组成的集合
s.sysmmetric_difference_update(t) 计算s与t的对称差集，并将结果放入s s.isdisjoint(t) 如果s和t没有相同项，则返回True
s.issubset(t) 如果s是t的一个子集，则返回True
s.issuperset(t) 如果s是t的一个超集，则返回True
附上源码：
class set(object):
"""
set() -> new empty set object
set(iterable) -> new set object Build an unordered collection of unique elements.
"""
def add(self, *args, **kwargs): # real signature unknown
"""
Add an element to a set，添加元素 This has no effect if the element is already present.
"""
pass def clear(self, *args, **kwargs): # real signature unknown
""" Remove all elements from this set. 清除内容"""
pass def copy(self, *args, **kwargs): # real signature unknown
""" Return a shallow copy of a set. 浅拷贝 """
pass def difference(self, *args, **kwargs): # real signature unknown
"""
Return the difference of two or more sets as a new set. A中存在，B中不存在 (i.e. all elements that are in this set but not the others.)
"""
pass def difference_update(self, *args, **kwargs): # real signature unknown
""" Remove all elements of another set from this set. 从当前集合中删除和B中相同的元素"""
pass def discard(self, *args, **kwargs): # real signature unknown
"""
Remove an element from a set if it is a member. If the element is not a member, do nothing. 移除指定元素，不存在不保错
"""
pass def intersection(self, *args, **kwargs): # real signature unknown
"""
Return the intersection of two sets as a new set. 交集 (i.e. all elements that are in both sets.)
"""
pass def intersection_update(self, *args, **kwargs): # real signature unknown
""" Update a set with the intersection of itself and another. 取交集并更更新到A中 """
pass def isdisjoint(self, *args, **kwargs): # real signature unknown
""" Return True if two sets have a null intersection. 如果没有交集，返回True，否则返回False"""
pass def issubset(self, *args, **kwargs): # real signature unknown
""" Report whether another set contains this set. 是否是子序列"""
pass def issuperset(self, *args, **kwargs): # real signature unknown
""" Report whether this set contains another set. 是否是父序列"""
pass def pop(self, *args, **kwargs): # real signature unknown
"""
Remove and return an arbitrary set element.
Raises KeyError if the set is empty. 移除元素
"""
pass def remove(self, *args, **kwargs): # real signature unknown
"""
Remove an element from a set; it must be a member. If the element is not a member, raise a KeyError. 移除指定元素，不存在保错
"""
pass def symmetric_difference(self, *args, **kwargs): # real signature unknown
"""
Return the symmetric difference of two sets as a new set. 对称差集 (i.e. all elements that are in exactly one of the sets.)
"""
pass def symmetric_difference_update(self, *args, **kwargs): # real signature unknown
""" Update a set with the symmetric difference of itself and another. 对称差集，并更新到a中 """
pass def union(self, *args, **kwargs): # real signature unknown
"""
Return the union of sets as a new set. 并集 (i.e. all elements that are in either set.)
"""
pass def update(self, *args, **kwargs): # real signature unknown
""" Update a set with the union of itself and others. 更新 """
pass
不可变集合：
help(frozenset)
练习：寻找差异
# 数据库中原有
old_dict = {
"#1":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 },
"#2":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 },
"#3":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 }
}
# cmdb 新汇报的数据
new_dict = {
"#1":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 800 },
"#3":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 },
"#4":{ 'hostname':'c2', 'cpu_count': 2, 'mem_capicity': 80 }
}
old_set=set(old_dict)
new_set=set(new_dict) del_set=old_set.difference(new_set)
add_set=new_set.difference(old_set)
flush_set=old_set.intersection(new_set) for i in del_set:
old_dict.pop(i) for i in add_set:
old_dict[i]=new_dict[i] for i in flush_set:
old_dict[i] = new_dict[i]
print(old_dict)
深拷贝浅拷贝
拷贝意味着对数据重新复制一份，对于拷贝有两种深拷贝，浅拷贝两种拷贝，不同的拷贝有不同的效果。拷贝操作对于基本数据结构需要分两类进行考虑，一类是字符串和数字，另一类是列表、字典等。如果要进行拷贝的操作话，要import copy。
1、数字和字符串
对于数字和字符串而言，深拷贝，浅拷贝没有什么区别，因为对于数字数字和字符串一旦创建便不能被修改，假如对于字符串进行替代操作，只会在内存中重新生产一个字符串，而对于原字符串，并没有改变，基于这点，深拷贝和浅拷贝对于数字和字符串没有什么区别，下面从代码里面说明这一点。
import copy
s='abc'
print(s.replace('c','222')) # 打印出 ab222
print(s) # s='abc' s并没有被修改
s1=copy.deepcopy(s)
s2=copy.copy(s) #可以看出下面的值和地址都一样，所以对于字符串和数字，深浅拷贝不一样，数字和字符串一样就不演示了，大家可以去试一下
print(s,id(s2)) # abc 1995006649768
print(s1,id(s2)) # abc 1995006649768
print(s2,id(s2)) # abc 1995006649768
2、字典、列表等数据结构
对于字典、列表等数据结构，深拷贝和浅拷贝有区别，从字面上来说，可以看出深拷贝可以完全拷贝，浅拷贝则没有完全拷贝，下面先从内存地址分别来说明，假设 n1 = {"k1": "wu", "k2": 123, "k3": ["alex", 456]}。
浅拷贝在内存中只额外创建第一层数据 深拷贝在内存中将所有的数据重新创建一份
下面从代码上来进行说明，copy.copy()与list.copy(),dict.copy()都属于浅复制
import copy
n1 = {"k1": "wu", "k2": 123, "k3": ["alex", 456]}
n2=copy.copy(n1) # 浅拷贝
n3=copy.deepcopy(n1) # 深拷贝
print(n1,id(n1),id(n1['k1']),id(n1['k3']))
print(n2,id(n2),id(n2['k1']),id(n2['k3']))
print(n3,id(n3),id(n3['k1']),id(n3['k3'])) # 从下面打印的值结合上面的图就可以很好的理解，
# {'k3': ['alex', 456], 'k2': 123, 'k1': 'wu'} 2713748822024 2713753080528 2713755115656
# {'k3': ['alex', 456], 'k2': 123, 'k1': 'wu'} 2713755121416 2713753080528 2713755115656
# {'k3': ['alex', 456], 'k2': 123, 'k1': 'wu'} 2713753267656 2713753080528 2713754905800
补充
一 、enumrate
为一个可迭代的对象添加序号，可迭代的对象你可以理解成能用for循环的就是可迭代的。默认是编号是从0开始，可以设置从1开始
li = ["手机", "电脑", '鼠标垫', '游艇']
for k, i in enumerate(li，1):
print(k,i)
1 手机
2 电脑
3 鼠标垫
4 游艇
二、range和xrange
在python2中有xrange和range，其中range会一次在内存中开辟出了所需的所有资源，而xrange则是在for循环中循环一次则开辟一次所需的内存，而在Python3中没有xrange，只有range ，但是python3的range代表的就是xrange。range用来指定范围，生成指定的数字。
for i in range(10): #循环输出所生成的 0-9
print(i) for i in range(1,10,2): #输出所生成的 1 3 5 7 9
print(i)
练习：
一、元素分类
有如下值集合 [11,22,33,44,55,66,77,88,99]，将所有大于 66 的值保存至字典的第一个key中，将小于 66 的值保存至第二个key的值中。即： {'k1': 大于66的所有值, 'k2': 小于66的所有值}
l= [11,22,33,44,55,66,77,88,99]
bignum=[]
smallnum=[]
dir={}
for num in l:
if num>66:
bignum.append(num)
if num<66:
smallnum.append(num)
else:
pass
dir['k1']=bignum
dir['k2']=smallnum
print(dir)
二、查找
查找元素，移动空格，并查找以 a或A开头 并且以 c 结尾的所有元素。
li = ["alec", " aric", "Alex", "Tony", "rain"]
tu = ("alec", " aric", "Alex", "Tony", "rain")
dic = {'k1': "alex", 'k2': ' aric', "k3": "Alex", "k4": "Tony"}
li = ["alec", " aric", "Alex", "Tony", "rain"]
tu = ("alec", " aric", "Alex", "Tony", "rain")
dic = {'k1': "alex", 'k2': ' aric', "k3": "Alex", "k4": "Tony"} for i in li:
if i.strip().capitalize().startswith('A') and i.strip().endswith('c'):
print(i)
for i in tu:
if i.strip().capitalize().startswith('A') and i.strip().endswith('c'):
print(i)
for i in dic.values():
if i.strip().capitalize().startswith('A') and i.strip().endswith('c'):
print (i)
三、输出商品列表，用户输入序号，显示用户选中的商品
商品 li = ["手机", "电脑", '鼠标垫', '游艇']
#方法一
l1=[1,2,3,4]
l2=["手机", "电脑", '鼠标垫', '游艇']
d=dict(zip(l1,l2))
print(d)
num=input("请输入商品编号：")
print("你选择的商品为 %s" %d[int(num)]) #方法二
li = ["手机", "电脑", '鼠标垫', '游艇']
for k, i in enumerate(li):
print(k,i)
k=input("请输入商品编号：")
print("你选择的商品为 %s" % li[int(k)])
购物车游戏
四、购物车
功能要求：
- 要求用户输入总资产，例如：2000
- 显示商品列表，让用户根据序号选择商品，加入购物车
- 购买，如果商品总额大于总资产，提示账户余额不足，否则，购买成功。
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product = [ ("iphone",5800), ("watch",380), ("bike",800), ("book",120), ("computer",4000)]shopping_car = []salary = input("input your salary: ")if salary.isdigit(): salary = int(salary) while True: for i in enumerate(product): print(i) user_choice = input(">>>或者q:") if user_choice.isdigit(): user_choice = int(user_choice) if user_choice >= 0 and user_choice < len(product): p_item = product[user_choice] if salary >= p_item[1]: shopping_car.append(p_item[0]) salary -= p_item[1] print("你购买了\033[32m%s\033[0m,你的余额剩余\033[31m%s\033[0m" % (p_item[0], salary)) else: print("\033[31m你的余额不足\033[0m") else: print("你输入的项目[%s]不存在,请重新输入" % user_choice) elif user_choice == 'q': print("你购买了这些商品:".center(30,"-")) for i in shopping_car: print("\033[32m%s\033[0m" %i) print("\033[31m余额%s\033[0m" %salary) exit() else: print("你输入的[%s]不存在" % user_choice)else: print("你输入的金额不正确！请重新输入金额！") |
五、用户交互，显示省市县三级联动的选择
dic = {
"河北": {
"石家庄": ["鹿泉", "藁城", "元氏"],
"邯郸": ["永年", "涉县", "磁县"],
},
"湖南": {
"长沙":['a','b','c'],
"株洲":['d','e','f']
},
"湖北": {
"武汉":['g','h','i'],
"黄石":['j','k','l']
}
}
for k in dic.keys():
print(k)
flag=True
while flag:
n=input("请输入你所在省：")
for k in dic.keys():
if n in dic.keys():
if k == n:
for i in dic[n].keys():
print(i)
w = input("请输入你所在的城市：")
for i in dic[n].keys():
if w in dic[n].keys():
if i == w:
for k in dic[n][w]:
print(k)
s=input("请输入你所在的县：")
for j in dic[n][w]:
if s in dic[n][w]:
if j==s:
print("你所在的位置是：%s省%s市%s县" % (n,w,s))
flag = False
break
else:
print('不存在，请重新输入')
break
else:
print('不存在，请重新输入')
break
else:
print('不存在，请重新输入')
break
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