1.函数目录
函数名
功能
help
查看指定对象的帮助信息
sum
返回迭代对象相加的结果
dir
列出指定对象的属性信息
bytes
把字符串转为bytes
all
判断可选代对象的每个元素是否都为True值,返回布尔类型
any
判断可迭代对象的元素是否有为True值的元素,返回布尔类型
enumerate
用于将一个可遍历的数据对象(如列表、元组或字符串)组合为一个索引序列,同时列出数据和数据下标
zip
合并多个序列类型
filter
根据提供的函数返回为真的一个新序列
map
根据提供的函数对指定序列做映射
sorted
对指定的序列进行排序
callable
用来检测对象是否可被调用,返回布尔类型
globals
函数会以字典格式返回当前位置的全部全局变量
locals
返回本地作用域中的所有名字
getattr
函数用于返回一个对象属性值
hasattr
用于判断对象是否包含对应的属性
delattr
用于删除属性
setattr
用于设置属性值,该属性不一定是存在的
iter
用来生成迭代器
next
返回可迭代对象中的下一个元素值
super
用于调用父类(超类)的一个方法
2.函数详解
(1)help
help ( print )
Help on built- in function print in module builtins:
print ( . . . )
print ( value, . . . , sep= ' ' , end= '\n' , file = sys. stdout, flush= False )
Prints the values to a stream, or to sys. stdout by default.
Optional keyword arguments:
file : a file - like object ( stream) ; defaults to the current sys. stdout.
sep: string inserted between values, default a space.
end: string appended after the last value, default a newline.
flush: whether to forcibly flush the stream.
(2)sum
sum ( [ 11 , 22 , 33 ] )
sum ( [ 11 , 22 , 33 ] , 100 )
66
166
(3)dir
dir ( [ ] )
[ '__add__' , '__class__' , '__contains__' , '__delattr__' , '__delitem__' , '__dir__' , '__doc__' , '__eq__' , '__format__' , '__ge__' , '__getattribute__' , '__getitem__' , '__gt__' , '__hash__' , '__iadd__' , '__imul__' , '__init__' , '__init_subclass__' , '__iter__' , '__le__' , '__len__' , '__lt__' , '__mul__' , '__ne__' , '__new__' , '__reduce__' , '__reduce_ex__' , '__repr__' , '__reversed__' , '__rmul__' , '__setattr__' , '__setitem__' , '__sizeof__' , '__str__' , '__subclasshook__' , 'append' , 'clear' , 'copy' , 'count' , 'extend' , 'index' , 'insert' , 'pop' , 'remove' , 'reverse' , 'sort' ]
(4)bytes
bytes ( "内置函数" , encoding= "utf-8" )
b'\xe5\x86\x85\xe7\xbd\xae\xe5\x87\xbd\xe6\x95\xb0'
(5)all
功能:判断可选代对象的每个元素是否都为True值,返回布尔类型
all ( [ 11 , 22 , 33 ] )
all ( [ 11 , 22 , 33 , 0 ] )
all ( [ 11 , 22 , 33 , [ ] ] )
True
False
False
(6)any
功能:判断可迭代对象的元素是否有为True值的元素,返回布尔类型
any ( [ 11 , 0 , 0 , 0 ] )
any ( [ 0 , 0 , 0 , 0 , 0 ] )
True
False
(7)enumerate
功能:用于将一个可遍历的数据对象(如列表、元组或字符串)组合为一个索引序列,同时列出数据和数据下标
for i in enumerate ( [ 11 , 22 , 33 ] ) :
print ( i)
( 0 , 11 )
( 1 , 22 )
( 2 , 33 )
(8)zip
a= zip ( [ 1 , 2 , 3 ] , [ "a" , "b" , "c" ] )
a
list ( a)
b= zip ( [ 1 , 2 , 3 ] , [ "a" , "b" ] )
list ( b)
< zip object at 0x000001737E5D3A00 >
[ ( 1 , 'a' ) , ( 2 , 'b' ) , ( 3 , 'c' ) ]
[ ( 1 , 'a' ) , ( 2 , 'b' ) ]
(9)filter
功能:根据提供的函数返回为真的一个新序列
相当于过滤器
a= [ 1 , 2 , 3 , 4 , 5 ]
temp= filter ( lambda x: x% 2 == 0 , a)
temp
list ( temp)
def f ( x) :
return x% 2 == 0
temp= filter ( f, a)
list ( temp)
< filter object at 0x000001737E54F5E0 >
[ 2 , 4 ]
[ 2 , 4 ]
(10)map
功能:根据提供的函数对指定序列做映射
相当于映射器
temp= map ( lambda x: x+ 1 , [ 1 , 2 , 3 ] )
temp
list ( temp)
temp= map ( lambda x, y: x+ y, [ 1 , 2 , 3 ] , [ 11 , 22 , 33 ] )
list ( temp)
< map object at 0x00000148DBB48790 >
[ 2 , 3 , 4 ]
[ 12 , 24 , 36 ]
(11)sorted
sorted ( [ 22 , 5 , 9 , 11 ] )
sorted ( [ 22 , 5 , 9 , 11 ] , reverse= True )
dt= { "huawei" : 123 , "zw" : 45 , "lenovo" : 78 }
sorted ( dt. items( ) , key= lambda x: x[ 1 ] )
sorted ( dt. items( ) , key= lambda x: x[ 1 ] , reverse= True )
[ 5 , 9 , 11 , 22 ]
[ 22 , 11 , 9 , 5 ]
[ ( 'zw' , 45 ) , ( 'lenovo' , 78 ) , ( 'huawei' , 123 ) ]
[ ( 'huawei' , 123 ) , ( 'lenovo' , 78 ) , ( 'zw' , 45 ) ]
(12)callable
a= 1
def f ( x) :
return x% 2 == 0
callable ( a)
callable ( f)
callable ( print )
False
True
True
(13)globals
a= 1
print ( globals ( ) )
{ '__name__' : '__main__' , '__doc__' : None , '__package__' : None , '__loader__' : < class '_frozen_importlib.BuiltinImporter' > , '__spec__' : None , '__annotations__' : { } , '__builtins__' : < module 'builtins' ( built- in ) > , 'a' : 1 }
(14)locals
def add ( a, b) :
print ( locals ( ) )
return a+ b
add( 11 , 22 )
{ 'a' : 11 , 'b' : 22 }
(15)getattr
a= [ 11 , 22 , 33 ]
getattr ( a, "append" )
getattr ( a, "append" ) ( 55 )
a
< built- in method append of list object at 0x00000236F36D6AC0 >
[ 11 , 22 , 33 , 55 ]
(16)hasattr
a= [ 11 , 22 , 33 ]
hasattr ( a, "append" )
hasattr ( a, "append1" )
True
False
(17)delattr
class A ( object ) :
def __init__ ( self, name, age) :
self. name = name
self. age = age
a = A( "hhh" , 66 )
print dir ( a)
delattr ( a, "age" )
print dir ( a)
[ '__doc__' , '__init__' , '__module__' , 'age' , 'name' ]
[ '__doc__' , '__init__' , '__module__' , 'name' ]
(18)setattr
class A ( object ) :
name = "xiaoniao"
a = A( )
setattr ( a, "age" , 33 )
print ( a. age)
33
(19)iter
a= [ 11 , 22 , 33 ]
type ( a)
a= iter ( a)
type ( a)
< class 'list' >
< class 'list_iterator' >
(20)next
a= [ 11 , 22 , 33 ]
a= iter ( a)
next ( a)
next ( a)
next ( a)
11
22
33
(21)super
class A ( object ) :
def __init__ ( self) :
print ( "A1" )
print ( "A2" )
class B ( A) :
def __init__ ( self) :
print ( "B1" )
super ( B, self) . __init__( )
print ( "B2" )
b= B( )
B1
A1
A2
B2