2024年7月19日发(作者：)

内置函数

原始文档来自于

python V2.7.2

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abs ()

all()

any ()

basestring()

bin()

bool()

bytearray ()

callable()

chr ()

classmethod()

cmp()

compile ()

complex ()

delat

七

r ()

divmod ()

enumerate ()

eval()

exeefile ()

fileO

f 11 ter

1

()

float()

forma

七（）

inputs ()

int()

isinstance()

issubclass()

iter ()

len ()

lis

七

（）

locals()

long ()

map()

max ()

memoryview()

min ()

nex

七（

）

open()

ord()

pow()

prin

七

（）

property()

range()

raw input()

reduce()

reload()

repr()

reversed()

round()

set ()

setattr()

slice ()

sorted ()

sta

七

ium

巳七

hod

()

str ()

sum ()

super ()

tuple ()

type ()

nnichr ()

unicode ()

vars()

xrange()

zip()

import ()

apply ()

buffer ()

coerce ()

in

七

ern ()

frozenset()

getattr ()

globals ()

hasattr ()

hash ()

help()

hex ()

id()

diet ()

objec

七

（）

oct ()

dir()

1

■取绝对值

abs(x)

Return the absolute value of a number. The argument may be a plain or long integer or a

floati ng point numb er. If the argume nt is a complex numb er, its mag nitude is retur ned.

如

果你不知道绝对值什么意思”那就要补一下小学数学了!

基本用法

»> abs (-3)

3

2.

a{ite rabid}

Return True if all elements of the iterable are true (or if the iterable is empty). Equivalent to:

3.

an y {iterable

Return True if any element of the iterable is true. If the iterable is empty, return False.

Equivale nt to:

4.

basestri ng()

This abstract type is the superclass for str and unicode. It can not be called or in sta ntiated, but

it can be used to test whether an object is an instanee of str or unicode. isinstance(obj

z

basestri

ng) is equivale nt to isinsta nce(obj, (str; un icode)).

是字符串和字符编码的超类，是抽象类型。不能被调用或者实例化。可以用来判断实例是否为字符串 或

者字符编码。

方法：

5.

二进制转换

bin

(

A

)

Con vert an integer nu mber to a binary string. The result is a valid Python expressi on. If xs not

a Python int object, it has to define an _index_() method that returns an integer.

转换成二进制表达 方法:

»> bin (8)

■OblOOO

1

6

•布尔类型

bool([Aj)

Convert a value to a Boolean, using the standard truth testing procedure. If % is false or omitted,

this returns False; otherwise it returns True, bool is also a class, which is a subclass of int. Class

bool cannot be subclassed further. Its only in stances are False and True

布尔类型的转化 用法:

»> tool (0)

False

»> tool ( [0])

True

7.

二进制数组的转化

bytear ray ([so6/rce[

z

encoding, errors)

Return a new array of bytes. The bytearray type is a mutable sequenee of integers in the range

0 <= x < 256. It has most of the usual methods of mutable sequences, described in Mutable

Sequence Types

】

as well as most methods that the str type has, see String Methods.

The optional source parameter can be used to initialize the array in a few different ways:

• If it is a string, you must also give the encoding (a nd opti on ally, errors

parameters; bytearray() then converts the string to bytes using ()

・

• If it is an integer, the array will have that size and will be initialized with null

bytes.

• If it is an object con forming to the interface, a read

・

only buffer of the

object will be used to initialize the bytes array.

• If it is an iterable, it must be an iterable of integers in the range 0 <= x < 256,

which are used as the initial contents of the array.

Without an argument, an array of size 0 is created

・

8.

calla ble(oZy&0

Return True if the oZyQuf argument appears callable, False if not If this returns true, it is still

possible that a call fails, but if it is false, calling object

N

W never succeed. Note that classes are

callable (calli ng a class returns a new instan ce); class in stances are callable if they have a _call_()

method.

9

•数字转化成字符

chr(/)

Return a string of one character whose ASCII code is the integer Z For example, chr(97) retur ns

the stri ng 'a*. This is the in verse of ord()

・

The argume nt must be in the range [0..255], in

elusive; ValueError will be raised if /is outside that ran ge. See also un ichr()

・

用法：

»> chr (200)

'xc8'

、、J

:L0・

classmethod(^//7rf/b/7

)

Return a class method for function.

A class method receives the class as implicit first argument, just like an in stance method

receives the instance. To declare a class method, use this idiom:

•两两比较

cmpU

助

Compare the two objects xand yand return an integer according to the outcome.

The return value is negative if x < y, zero if x = = y and strictly positive if x > y.

X

小于

X

输出负(

J) ,X

等于

Y

输出零

(

0) ,X

大于

Y

输岀正

(

1)

用法：

»> cir.p (

rr

f

r

45)

1

»> cir.p (45

f

n

f

r,

)

-1

12.

compile(sot//V£ filename, modj flag* dont_inheriti)

Compile the source into a code or AST object Code objects can be executed by an exec

statement or evaluated by a call to eval()

・

source can either be a string or an AST object. Refer

to the ast module documentation for information on how to work with AST objects.

13.

complex

([厂

e

就

Create a complex number with the value real + imag^] or convert a string or number to a

complex number. If the first parameter is a string, it will be interpreted as a complex number

and the function must be called without a second parameter. The second parameter can never

be a string. Each argument may be any numeric type (including complex). If /mag is omitted, it

defaults to zero and the function serves as a numeric conversion function like into, long() and

float()

・

If both arguments are omitted, returns Oj.

14.

delattr(c>Zyect name)

This is a relative of setattr()

・

The arguments are an object and a string. The string must be the

name of one of the object' s attributes. The function deletes the named attribute, provided the

object allows it. For example, delattr(x, 'foobar') is equivale nt to del .

15

•字典

diet

([曰勿)

Create a new data dictionary, opti on ally with items take n from arg. The dicti onary type

is described in Mapping Types — diet.

For other containers see the built in list, set, and tuple classes, and the collections

module.

16

•很重要的函数

f

属性输出

dr ([object

Without arguments, return the list of names in the current local scope. With an argument,

attempt to return a list of valid attributes for that object.

方法

»> dir ()

[

1

builtins

1

doc

1

9

1

nair.e

1

9

1

package

1

a

1

all

1

]

17.

divmod

(

3 b)

Take two (non complex) numbers as arguments and return a pair of numbers consisting of their

quotient and remai nder whe n using long division. With mixed opera nd types, the rules for

binary arithmetic operators apply. For plain and long integers, the result is the same as (a // b

z

a % b). For floating point numbers the result is (q, a % b)

z

where q is usually (a / b)

but may be 1 less tha n that. I n any case q*b + a%bis very close to a, if a % b is non-zero it has

the same sign as b, and 0 <= abs(a % b) < abs(b).

enumerate(S6»gt/e/7ue[, start=0^}

Return an enumerate object, sequence must be a sequenee, an iterator, or some other object

which supports iteration. The next() method of the iterator returned by enumerateQ returns a

tuple containing a count (from s

扫

//which defaults to 0) and the corresponding value obtained

from iterating over iterable. enumerate() is useful for obtaining an indexed series: (0, seq[0]), (1,

seq[l]), (2, seq[2])

19.

eia{expression[, global* locals^)

The arguments are a string and optional globals and locals. If provided, globals must be a

dicti on ary. If provided, locals ca n be any mappi ng object.

Changed in version 2.4: formerly locals was required to be a dictionary.

20.

execfi I e(filename, global

丸

localsW)

This functi on is similar to the exec statement, but parses a file in stead of a string. It is different

from the import statement in that it does not use the module administration — it reads the file

unconditionally and does not create a new module.

和

exec

很相似的函数

21.

file

(佻门日刃乩

mod

気

bufsize)

Constructor function for the file type, described further in section File Objects. The constructor' s

arguments are the same as those of the open() built-in function described below.

Whe n openi ng a file, it s preferable to use open() in stead of in voki ng this con structor

directly, file is more suited to type testing (for example, writing isinstance(f

z

file)).

22.

unction, iterab/e)

Con struct a list from those eleme nts of iterable for which function retur ns true. iterab/e

may be either a sequenee, a container which supports iteration, or an iterator.

If iterable is a string or a tuple, the result also has that type; otherwise it is always a list.

If function is None, the identity function is assumed, that is, all elements of iterable that

are false are removed.

Note that filter(function

z

iterable) is equivalent to [item for item in iterable

讦

function

(item)]

讦

function is not None and [item for item in iterable if item] if fun ction is None.

See r() and rfalse() for iterator versions of this function,

in eluding a variation that filters for eleme nts where the function retur ns false.

23

•浮点数值转化

float([Aj)

用法：

»> float (345)

345 ・0

24.

format

(旧加

L format_spe

①

Con vert a value to a "formatted" represe ntati on, as con trolled by format_spec. The

interpretation of format_specNW depend on the type of the i^/6/eargument, however there is

a standard formatting syntax that is used by most built-in types: Format Specification Min i

・

Language.

25

froze n set([ iterab/e)

Retur n a frozenset object, opti on ally with eleme nts taken from iterable. The froze nset type is

described jn Set Types — set, frozenset.

For other containers see the built in diet, list, and tuple classes, and the collections module.

26.

getattr(oZyQct nam^, default)

Return the value of the named attribute of object, name must be a string. If the string is the

name of one of the object s attributes, the result is the value of that attribute. For example,

getattr(x

z

^oobar') is equivale nt to . If the n amed attribute does not exist, default is

returned

讦

provided, otherwise AttributeError is raised.

27

•全局参数

globals()

Return a dictionary representing the current global symbol table. This is always the dictionary of

the current module (inside a function or method, this is the module where it is defined, not the

module from which it is called).

28.

hasattr(oZyQd

；

namd)

Return the hash value of the object (if it has one). Hash values are integers. They are used to

quickly compare dictionary keys during a dictionary lookup

・

Numeric values that compare

equal have the same hash value (even if they are of different types, as is the case for 1 and 1.0).

29.

hash(o$QC

Return the hash value of the object (if it has one). Hash values are integers. They are used to

quickly compare dictionary keys during a dictionary lookup

・

Numeric values that compare

equal have the same hash value (even if they are of different types, as is the case for 1 and 1.0).

30

•很重要的帮助函数方法

help([oZy&4)

31.

十六进制转化

hex

(

A

)

Con vert an in teger nu mber (of any size) to a hexadecimal stri ng. The result is a valid Pyth on

expressi on.

用法：

»> hex (16)

•OxlO*

32

•内存地址

d(ob/ect

)

Return the "identity" of an object. This is an integer (or Iong integer) which is guaranteed to be

unique and constant for this object during its lifetime. Two objects with non

・

overlapping

lifetimes may have the same id() value.

如果想知道某个对象的内存地址，用这个内置函数，返回的是

10

进制的地址。

33.

input([p/z?/77pZ])

Equivale nt to eval(raw_input(prompt)).

34.

Convert a string or number to a plain integer. If the argument is a string, it must contain a

possibly signed decimal number representable as a Python integer, possibly embedded in

whitespace. The base parameter gives the base for the conversion (which is 10 by default) and

may be any integer in the range [2, 36], or zero. If base is zero, the proper radix is determined

based on the contents of string; the interpretation is the same as for integer literals. (See

Numeric literals

、

If base is specified and x s not a string, TypeError is raised

・

Otherwise, the

argument may be a plain or long integer or a floating point number.

Con version of floati ng point nu mbers to integers truncates (towards zero). If the argume nt is

outside the in teger range a long object will be returned instead .If no argume nts are given,

returns 0.

35.

isinstance(o/yQd c/assinfd}

Return true if the o/yQctargument is an instanee of the classinfo argument, or of a (direct or

indirect) subclass thereof. Also return true

讦

classinfo is a type object (new-style class) and

object is an object of that type or of a (direct or in direct) subclass thereof. If object is not a class

in stance or an object of the give n type, the function always retur ns false. If classinfo is neither

a class object nor a type object, it may be a tuple of class or type objects, or may recursively

contain other such tuples (other sequence types are not accepted). If classinfo is not a class,

type, or tuple of classes, types, and such tuples, a TypeError exception is raised.

36.

issubclass(cZ?55

；

dassinfo}

Return true

讦

class is a subclass (direct or indirect) of classinfo. A class is considered a subclass

of itself, classinfo may be a tuple of class objects, in which case every entry in classinfo ^W be

checked. In any other case, a TypeError exception is raised.

37.

导管■窗口 •容器•数据的窗口化

iter(o[, sentine

心

Return an iterator object The first argument is interpreted very differently depending on the

presenee of the second argument. Without a second argument, o must be a collection object

which supports the iteration protocol (the _iter_() method), or it must support the sequenee

protocol (the _getitem_() method with integer arguments starting at 0). If it does not support

either of those protocols, TypeError is raised. If the second argument, sentinel, is given, then o

must be a callable object. The iterator created in this case will call o with no arguments for each

call to its next() method; if the value returned is equal to sentinel, Stoplteration will be raised,

otherwise the value will be returned.

iter

(现

sentinel

回一个迭代器对象。第一个参数根据第二个参数进行编译。第二参数为空,

O

必 须是支

持迭代器的协议

(the _iter_() method)

的集合对象，或者支持顺序协议

(the _getitem_()method with

integer arguments staring at 0).

如果不支持其中任意一种协议,程序 将会抛出类型异常。

假如第二个参数被给出，然后

O

必须是一个可被调用的对象。迭代器被创建万一

will

掉用

O with

没有

参数

for each call to its next() method;

如果返回值和初始值相同

I, Stoplteration

将会抛出, 否则值会

被返回！

38

•计算长度（常用函数

） len(s) Return the length (the number of items) of an object The

argument may be a sequenee (string, tuple or list) or a mapping (dictionary).

用法：

»> a=

rr

sdfdf

rr

»> len (a)

5

39

•转化成列表

WsX.([iterable[}

Return a list whose items are the same and in the same order as iterable s items, iterable may

z

be either a sequenee, a container that supports iteration, or an iterator object. If iterable is

already a list, a copy is made and returned, similar to iterable[:]. For instance

z

list('abc') returns

fa', 'b *c'] and list( (l

z

2, 3)) returns [1, 2, 3]. If no argument is given, returns a new empty list,[].

40.

Iocals()

Update and return a dictionary represent!ng the current local symbol table. Free variables are

returned by locals

。

when it is called in function blocks, but not in class blocks

・

Update and return a dictionary

更新禾口返回字典

41.

long([A[/ base)

Con vert a stri ng or nu mber to a long in teger. If the argume nt is a stri ng it must contain a

possibly signed number of arbitrary size, possibly embedded in whitespace. The base

argument is interpreted in the same way as for into, and may only be given when xs a string.

Otherwise, the argument may be a plain or long integer or a floating point number, and a long

integer with the same value is returned. Con version of floating point numbers to integers

truncates (towards zero). If no arguments are given, returns OL.

42.

malfunction, iterable,...)

Apply function to every item of iterable a nd return a list of the results. If additi onal iterable

arguments are passed, function must take that many arguments and is applied to the items

from all iterables in parallel. If one iterable is shorter than another it is assumed to be extended

with None items. If function is Non

巳

the identity function is assumed; if there are multiple

arguments, map() returns a list consisting of tuples containing the corresponding items from all

iterables (a kind of transpose operation). The

sequence or any iterable object; the result is always a list

43

•最大值

max(/?eA?Z?/e[

/

args..] [, key)

With a single argument iterable, return the largest item of a non

・

empty iterable (such as a

string, tuple or list). With more than one argument, return the largest of the arguments.

The optional Xreyargument specifies a argument ordering function like that used for ().

The Xr

即

argument

；

if supplied, must be in keyword form (for example, max(a

/

b

/

c

/

key=func)).

arguments may be a

memoryview(

(

?Zy)

Return a "memory view" object created from the given argument. See memoryview type for

more information.

45

・最小值

mr(iterab/e[, args..}[, key)

With a single argument iterable, return the smallest item of a non

・

empty iterable (such as a

string, tuple or list). With more than one argument, return the smallest of the arguments.

46

•迭代以后的函数

neyX{iterator[, defaults

Retrieve the next item from the iterator by calling its next() method. If default is given, it is

returned if the iterator is exhausted, otherwise Stopiteration is raised.

用法：

»> a=

rr

hellowolrd

rr

»> s=iter (a)

»> s .next ()

■h

1

47.

object()

Return a new featureless object, object is a base for all new style classes. It has the

methods that are common to all instances of new style classes.

4&

八进制字符串的转化

OCt（A）

Con vert an in teger nu mber (of any size) to an octal string. The result is a valid Pyth on

expression.

用法：

»> oct (8)

•oio*

49・

open( filename, mod

気

bufsize}

Open a file, returning an object of the file type described in section File Objects. If the file

cannot be opened, IOError is raised. When opening a file, it' s preferable to use open() in stead

of in voki ng the file con structor directly.

50

•字符转化成

ASCH

码

ord(c)

Given a string of length one, return an integer representing the Unicode code point of the

character when the argument is a unicode object, or the value of the byte when the argument

is an 8-bit string. For example, ord('a') returns the integer 97, ord(u'u2020

,

) retur ns 8224. This

is the in verse of chr() for 8

・

bit strings and of unichr() for un icode objects.

If a unicode argument is given and Python was built with UCS2 Unicode, then the character' s

code point must be in the range [0..65535] in elusive; otherwise the string length is two, and a

TypeError will be raised.

powg Xr N)

Return xto the power / if zis prese nt, return % to the power y modulo z (computed more efficie

ntly than pow(x, y) % z). The two-argument form pow(x, y) is equivale nt to using the power

operator: x**y.

52. print

函数原来本身就是函数。

print([o/yQ6t …]L sep=' ][

;

end='n}[, file

二

©

Print object^) to the stream file, separated by sepa nd followed by end. sep, end a nd file, if

present, must be given as keyword arguments.

53.

property

([如化屁£

fde^ doc]]])

Return a property attribute for new

・

sty/e classes (classes that derive from object).

54.

range([s

扫也

stop[, step}

起始位置，终止位置，步长

55

raw_input(0o/77pd)

If the prompt argume nt is prese nt, it is writte n to stan da rd output without a traili ng n

ewline.

用法:

»> s=raw_input (

r,

S 0

n

)

密码

2345

一

»> 3

,

2345

,

56.

redjce(funct/on, iterab/e[, initializer^

Apply function of two arguments cumulatively to the items of iterab/e, from left to right, so as

to reduce the iterable to a single value. For example, reduce(lambda x, y: x+y, [1, 2, 3, 4, 5])

calculates ((((l+2)+3)+4)+5). The left argument,

尢

is the accumulated value and the right

argument y, is the update value from the iterable. If the optional initializer s present, it is placed

before the items of the iterable in the calculation, and serves as a default when the iterable is

empty. If initializer is not give n and iterable con tai ns only one item, the first item is returned.

57

•重载模块

f

很重要的函数

veoa6{module)

58.

repr (object)

Return a string containing a printable representation of an object. This is the same value

yielded by conversions (reverse quotes). It is sometimes useful to be able to access this

operation as an ordinary function. For many types, this function makes an attempt to

return a string that would yield an object with the same value when passed to eval()

z

otherwise the representation is a string enclosed in angle brackets that contains the

name of the type of the object together with additional information often including the

name and address of the object. A class can control what this function returns for its

instances by defining a _repr_() method.

59.

reversed (se<7

)

Return a reverse iterator, seq must be an object which has a _reversed_() method or supports

the sequenee protocol (the _len_() method and the _getitem_() method with integer arguments

starting at 0).

60.

round(X/ /?])

Return the floating point value xrounded to n digits after the decimal point. If n is omitted, it

defaults to zero. The result is a floating point number. Values are rounded to the closest

multiple of 10 to the power minus rr,

讦

two multiples are equally close, rounding is done away

from 0 (so. for example, round(0.5) is 1.0 and round(-0.5) is

・

1.0).

61

•去重■但是不改变原始数据

set([/terab/e)

Retur n a new set, opti on ally with eleme nts take n from iterable. The set type is described in

Set Types — set, frozenset.

62.

seta

哲

name, valud)

This is the counterpart of getattr(). The arguments are an object, a string and an arbitrary value.

The string may name an existing attribute or a new attribute. The function assigns the value to

the attribute, provided the object allows it For example, setattr(x

z

'foobar

：

123) is equivale nt

to = 123

・

63

•切片起始位置

f

终止位置

f

步长

slice([s

朽也

stopl step)

Retur n a

动

de object represe nting the set of in dices specified by ran ge(start

z

stop, step). The

start a nd s

期

argume nts default to None. Slice objects have read-only data attributes start,

stop and step which merely return the argument values (or their default). They have no other

explicit functionality; however they are used by Numerical Python and other third party exte

nsions. Slice objects are also gen erated when extended in dexing syntax is used.

For example: a[start:stop:step] or a[start:stop

z

i]. See () for an alternate version that

returns an iterator.

用法

»>

s

=»dfsfrtr

n

»> s[0:3:l]

・ dfs'

64

排序

sorted(/terab/e[, cmp[, key{, reverse^

Return a new sorted list from the items in iterable.

用法

»> a=

rr

h; idf klsdj f 10

r,

»> sorted (a)

m '；

1

r

"d

1

r

l

d

,

r

1

r

1

f', ■h

1

r

■i

1

r

1

j

1

r

1

k

1

r r 'l

1

r "s']

65

•静态方法函数调用类方法的一种函数

staticmethod( function)

Return a static method for function.

66

•字符串转化

str([°Zy&M)

Return a string containing a nicely printable representation of an object. For strings, this

returns the string itself

・

The differenee with repr(object) is that str(object) does not

always attempt to return a string that is acceptable to evalQ; its goal is to return a

printable string. If no argument is given, returns the empty string

「.

67

•求和

sum("e/7

北何

starts

Sums start a nd the items of an iterable from left to right and retur ns the total, start

defaults to 0. The iterable 's items are normally numbers, and the start value is not

allowed to be a string.

6&

super

(妞

object-or-typ^}

Return a proxy object that delegates method calls to a pare nt or sibli ng class of type. This is

useful for accessing inherited methods that have been overridden in a class. The search order is

same as that used by getattr() except that the type itself is skipped.

69

•元组

tuple([/?e/^Z?/e])

Return a tuple whose items are the same and in the same order as iterable

z

s items, iterable may

be a sequenee, a container that supports iteration, or an iterator object. If iterable is already a

tuple, it is returned unchanged. For instance, tuple('abc') returns ('a,

1

'c*) and

tuple([l, 2, 3]) returns (1, 2, 3). If no argument is given, returns a new empty tuple,().

70

•类型

type(objecf

)

Return the type of an object The return value is a type object. The isinstance

。

built-in function

is recommended for testing the type of an object.

用法：

»> type (

M

2343

M

)

1

str

1

>

71.

unichr(/)

Return the Unicode string of one character whose Unicode code is the integer Z For

example, unichr(97) returns the string u'a'. This is the inverse of ord() for Unicode stri ngs.

The valid range for the argume nt depends how Pyth on was con figured

一

it may be

either UCS2 [O..OxFFFF] or UCS4 [O..OxlOFFFF]. ValueError is raised otherwise. For ASCII

and 8-bit strings see chr().

72.

unicode([oZyec?[

/

encoding, errors)

，

Return the Unicode string version of object using one of the following modes:

vars([oZyecZj)

Without an argument, act like locals

。.

74・

xrange([s

伯尬

stop{, step)

This functi on is very similar to range(), but retur ns an "xra nge object" in stead of a list.

This is an opaque sequenee type which yields the same values as the corresponding list,

without actually storing them all simultaneously. The advantage of xrange() over range()

is minimal (since xrange() still has to create the values when asked for them) except when

a very large range is used on a memory-starved machine or when all of the range s

z

elements are never used (such as when the loop is usually terminated with break).

75.

zp([iterab/e,…])

76.

_import_(name[, global

丸

local* from/is^, /ei/e/|]]])

Note

This is an advanced function that is not needed in everyday Python programming.

This function is invoked by the import statement. It can be replaced (by importing the

_builtin_ module and assigning to _builtin_._import_) in order to change semantics of the

import statement, but nowadays it is usually simpler to use import hooks (see PEP 302),

Direct use of _import_() is rare, except in cases where you want to import a module

whose name is only known at runtime.