Sixth: Python Foundation _6 built-in functions and common modules (i)

The content of this article

1. Built-in functions
2. anonymous functions
3. Re module
4. Time Module
5. Random module
6. OS Module
7. SYS module
8. JSON and Pickle modules
9. Shelve module

First, built-in functions

1. Definition

Built-in functions are also known as factory functions.

2. Common built-in functions

(1) ABS ()

#!/usr/binl/env Python#encoding:utf-8#author:yangleiprint (ABS (-1))

(2) All ()

#!/usr/binl/env Python#encoding:utf-8#author:yangleiprint (All ([Up, ' a ', None])) print (All ([]))

(3) any ()

#!/usr/binl/env Python#encoding:utf-8#author:yangleiprint (Any ([])) print (Any ([', ', None,false]) , False])) print (Any ([', none,false,1]))

(4) Bin (), Oct (), Hex ()

#!/usr/binl/env python#encoding:utf-8#author:yangleiprint (Bin) print (Oct) print (Hex (10))

(5) bytes ()

#!/usr/binl/env python#encoding:utf-8#author:yanglei#unicode----Encode----->bytesprint (' Hello '. Encode (' Utf-8 ') print (bytes (' Hello ', encoding= ' utf-8 '))

(6) Callable ()

#!/usr/binl/env python#encoding:utf-8#author:yangleiprint (callable (bytes)) Print (callable (ABS))

(7) Chr (), Ord ()

#!/usr/binl/env python#encoding:utf-8#author:yangleiprint (CHR) print (CHR) print (Ord (' # '))

(8) Int ()

#!/usr/binl/env Python#encoding:utf-8#author:yangleix=1print (Type (x)) X=int (2) print (type (x))

Complex (), float (), str (), list (), tuple (), dict () and int ()

(9) Set (), variable set

#!/usr/binl/env Python#encoding:utf-8#author:yangleis={1,2,3,4}print (type (s))

(Ten) Frozenset (), immutable collection

#!/usr/binl/env python#encoding:utf-8#author:yangleis1=frozenset ({1,2,3,4}) print (Type (S1))

(one) dir ()

#!/usr/binl/env python#encoding:utf-8#author:yangleiimport sys#sys.path# sys.argvprint (dir (SYS))

(Divmod) ()

#!/usr/binl/env Python#encoding:utf-8#author:yangleiprint (Divmod (10,3)) print (Divmod (102,20))

(+) Enumerate ()

#!/usr/binl/env python#encoding:utf-8#author:yangleil=[' A ', ' B ', ' C ']res=enumerate (L) for I in Res:    print (i) for Index,item in Enumerate (l):    print (Index,item)

(+) Globals (), locals (), view global scope and local scope

#!/usr/binl/env Python#encoding:utf-8#author:yangleiprint (Globals ())

() hash ()

#!/usr/binl/env Python#encoding:utf-8#author:yangleiprint (hash (' abcdefg123 ')) print (hash (' abcdefg123 '))

(+) Help ()

#!/usr/binl/env python#encoding:utf-8#author:yangleidef func ():    '    test function    : return:    ' '    Passprint (Help (func))

() ID (), which is a function implemented by the Python interpreter, only reflects the variable's address in memory, but not the actual memory address

#!/usr/binl/env Python#encoding:utf-8#author:yangleix=1print (ID (x)) def func ():    passprint (ID (func)) Print (func )

() Isinstance ()

#!/usr/binl/env Python#encoding:utf-8#author:yangleix=1print (Type (x) is int) print (isinstance (x,int))

Max (), Min ()

#!/usr/binl/env Python#encoding:utf-8#author:yangleiprint (Max ([1,2,3,10])) print (max ([' A ', ' B ']) print (min ([ 1,2,3,10]))

() Pow ()

#!/usr/binl/env python#encoding:utf-8#author:yangleiprint (POW (3,2,2)) #3 **2%2

(+) repr (), str ()

#!/usr/binl/env python#encoding:utf-8#author:yangleiprint (Type (str (1))) print (Type (repr (1)))

(a) reversed ()

#!/usr/binl/env python#encoding:utf-8#author:yangleil=[1, ' A ', 2, ' C ']print (list (Reversed (l))) print (L)

(at) Slice ()

#!/usr/binl/env Python#encoding:utf-8#author:yangleil=[1,2,3,4,5,6]print (L[0:4:2]) s=slice (0,4,2) print (L[s])

(sorted) ()

#!/usr/binl/env Python#encoding:utf-8#author:yangleil=[1,10,4,3,-1]print (sorted (l,reverse=true))

SUM ()

#!/usr/binl/env python#encoding:utf-8#author:yangleiprint (sum ([1, 2,3]) print (SUM (i-I in range (10)))

(+) VARs ()

#!/usr/binl/env python#encoding:utf-8#author:yangleiimport M1print (VARs (m1) = = m1.__dict__)

(+) Zip ()

#!/usr/binl/env python#encoding:utf-8#author:yangleis= ' Helloss ' l=[1,2,3,4,5]print (list (Zip (s,l)))

(+) __import__ ()

#!/usr/binl/env python#encoding:utf-8#author:yangleiimport sysm_name=input (' module>>: ') if m_name = = ' sys ':    m=__import__ (m_name) print (    m)    print (M.path) sys=__import__ (' sys ') print (SYS)

() round ()

#!/usr/binl/env Python#encoding:utf-8#author:yangleiprint (Round (3.565,2)) print (round (3.555,2))

Second, anonymous function

1. Definition

Anonymous functions:

(1) No name.

(2) The function body comes with return.

Application Scenarios for anonymous functions:
Apply to a one-time scenario for temporary use.

1. Role

#!/usr/binl/env python#encoding:utf-8#author:yangleidef func (x,y,z=1):    return X+y+zprint (func) Print (func ( ) print (lambda x,y,z=1:x+y+z) F=lambda x,y,z=1:x+y+zprint (f) Print (f ()

Third, re module

(1)

#!/usr/binl/env Python#encoding:utf-8#author:yangleiimport Reprint (Re.findall (' \w ', ' hello_ | yanglei 123 ') print ( Re.findall (' \w ', ' hello_ | yanglei 123 ')) Print (Re.findall (' \s ', ' hello_ | yanglei 123 \ t ')) print (Re.findall (' \s ', ' Hello_ | Yanglei 123 \ t ') print (Re.findall (' \d ', ' hello_ | yanglei 123 \ t ')) print (Re.findall (' \d ', ' hello_ | yanglei 123 \ t ') ) Print (Re.findall (' h ', ' hello_ | Hello h yanglei 123 \ t ')) print (Re.findall (' \ahe ', ' hello_ | Hello h yanglei 123 \ n \ t ') Print (Re.findall (' ^he ', ' hello_ | Hello h yanglei 123 \ t ')) print (Re.findall (' 123\z ', ' hello_ | Hello h yanglei 123 \ T  123 ') Print (Re.findall (' 123$ ', ' hello_ | Hello h yanglei 123 \ n \t123 ')) print (Re.findall (' \ n ', ' hello_ | Hello h yanglei 123 \ \t123 ') Print (Re.findall (' \ t ', ' hello_ | Hello h yanglei 123 \ n \t123 '))

(2). [] [^]

#!/usr/binl/env Python#encoding:utf-8#author:yangleiimport re#, which itself represents any one character print (Re.findall (' a.c ', ' a A1C a*c a2c ABC a C AAAAAAC AACC ')) #[] can have multiple characters inside, but only one print of multiple characters (Re.findall (' a[0-9][0-9]c ', ' a a12c A1c a*c a2c a C a\nc ', re. S)) Print (Re.findall (' a[a-za-z]c ', ' AAC ABC AAC a12c A1C a*c a2c a C a\nc ', re. S)) Print (Re.findall (' a[^a-za-z]c ', ' AAC ABC AAC a12c A1C a*c a2c a C a\nc ', re. S)) Print (Re.findall (' a[\+\/\*\-]c ', ' a-c a+c A/C AAC ABC AAC a12c A1C a*c a2c a C a\nc ', re. S))

(3) \: Escaped

#!/usr/binl/env Python#encoding:utf-8#author:yangleiimport Reprint (Re.findall (R ' a\\c ', ' a\c abc '))

(4)? * + {}: There are several characters on the left, if any, greedy match

#!/usr/binl/env python#encoding:utf-8#author:yangleiimport re#? The character on the left has 0 or 1 print (Re.findall (' ab ', ' AaB a ab aaaa ') ) #* left that character has 0 or infinitely print (Re.findall (' ab* ', ' a ab ABB abbb abbbb bbbbbb ') print (Re.findall (' ab{0,} ', ' A ab ABB abbb ABBBB BBBBBB ') #+ the left one character has 1 or infinitely print (Re.findall (' ab+ ', ' a ab ABB abbb abbbb bbbbbb ')) print (Re.findall (' Ab{1,} ', ' a ab ABB ABBB abbbb bbbbbb ') #{n,m} The character on the left has n-m times print (Re.findall (' ab{3} ', ' A ab ABB abbb abbbb bbbbbb ') print (Re.findall (' ab{2,3} ') , ' A ab ABB abbb abbbb bbbbbb '))

(5). *. *?

#!/usr/binl/env python#encoding:utf-8#author:yangleiimport re#.* greedy match print (Re.findall (' a.*c ', ' a123c456c ')) #.*? Non-greedy match print (Re.findall (' a.*?c ', ' a123c456c '))

(6) |

#!/usr/binl/env Python#encoding:utf-8#author:yangleiimport Reprint (Re.findall (' company|companies ', ' Too many Companies has gone bankrupt, and the next one is my company ') print (Re.findall (' compan|companies ', ' Too many companies hav e gone bankrupt, and the next one is my company '))

(7) (): Grouping

#!/usr/binl/env Python#encoding:utf-8#author:yangleiimport Reprint (Re.findall (' ab+ ', ' abababab123 ')) print ( Re.findall (' ab+123 ', ' abababab123 ') print (Re.findall (' ab ', ' abababab123 ')) print (Re.findall (' (AB) ', ' abababab123 ') Print (Re.findall (' (a) B ', ' abababab123 ')) print (Re.findall (' A (b) ', ' abababab123 ')) print (Re.findall (' (AB) + ', ' Abababab123 ') Print (Re.findall (' (?: AB) + ', ' abababab123 ')) print (Re.findall (' (AB) +123 ', ' abababab123 ')) print ( Re.findall (' (?: AB) +123 ', ' abababab123 ')) print (Re.findall (' (AB) + (123) ', ' abababab123 ')) print (Re.findall (' Compan ') (Y |ies) ', ' Too many companies has gone bankrupt, and the next one is my company ') print (Re.findall (' Compan (?: y|ies) ', ' Too ma NY companies has gone bankrupt, and the next one is my company '))

(8) Other methods of RE

#!/usr/binl/env Python#encoding:utf-8#author:yangleiimport Reprint (re.findall (' ab ', ' abababab123 ')) print ( Re.search (' ab ', ' abababab123 '). Group ()) Print (Re.search (' ab ', ' 12AASSSDDDSSSSSSSS3 ')) print (Re.search (' Ab ', ' 12aasssdddsssssssab3sssssss ') (group ()) Print (Re.search (' ab ', ' 123ab456 ') print (Re.match (' ab ', ' 123ab456 ')) print ( Re.split (' B ', ' ABCDE ')) print (Re.split (' [ab] ', ' ABCDE ')) print (Re.sub (' Xiaolan ', ' xiaohong ', ' Xiaolan make Love Xiaolan Xiaolan ', 1)) Print (Re.subn (' Xiaolan ', ' xiaohong ', ' Xiaolan make Love Xiaolan Xiaolan ', 1)) Print (Re.sub (' (\w+) (\w+) (\w+ (\w+) (\w+) ', R ' \5\2\3\4\1 ', ' Toms Make Love ') print (Re.sub (' (\w+) (. *) (\w+) ', R ' \3\2\1 ', ' Toms Make Love ')) obj= Re.compile (' \d{2} ') Print (Obj.search (' abc123eeee '). Group ()) Print (Obj.findall (' abc123eeee '))

Four, Time module

Module method

#!/usr/binl/env python#encoding:utf-8#author:yangleiimport Timeprint (Time.time ()) Print (Time.strftime ('%Y-%m-%d%x ') print (Time.localtime ()) print (Time.gmtime ()) #UTCprint (Time.localtime () tm_mon) print (Time.localtime (123123123 ) Print (Time.gmtime (123123123)) print (Time.mktime (Time.localtime ())) Print (Time.strftime ('%Y ', Time.gmtime ())) ' 2017-03-01 ' Print (time.strptime (' 2017-03-01 ', '%y-%m-%d ')) print (Time.ctime (12312312)) Print (Time.asctime ( Time.gmtime ()))

V. Random module

1. Module method

#!/usr/binl/env python#encoding:utf-8#author:yangleiimport Randomprint (Random.sample ([1, '% ', [4,5]],2)] Print ( Random.uniform (1,3)) Item=[1,3,5,7,9]random.shuffle (item) print (item)

2. Generate key Application

#!/usr/binl/env python#encoding:utf-8#author:yangleiimport randomdef make_code (n):    res= "for    I in range (n):        s1=str (Random.randint (0,9))        s2=chr (Random.randint (65,90))        res+=random.choice ([s1,s2])    return Resprint (Make_code (10))

VI. OS Module

Module method

#!/usr/binl/env python#encoding:utf-8#author:yangleiimport osprint (Os.listdir ('. ')) Print (Os.stat (' m1.py '). St_size) print (os.sep) print (os.linesep) print (OS.PATHSEP) print ([Os.sep,os.linesep, OS.PATHSEP]) Res=os.system (' dir. ') Print (' ====?> ', res) print (Os.path.dirname (R ' C:\a\b\c\d\a.txt ')) print (Os.path.basename (R ' C:\a\b\c\d\a.txt ')) Print (Os.path.split (R ' C:\a\b\c\d\a.txt ')) print (Os.stat (' m1.py '). St_atime) Print (Os.stat (' m1.py '). St_size) Print ( Os.path.getsize (' m1.py ')) print (Os.path.join (' c:\\ ', ' A ', ' B ', ' C ', ' D.txt ')) print (Os.path.join (' c:\\ ', ' A ', ' B ', ' D:\ \ ', ' C ', ' D.txt ') print (os.path.normcase (' c:/windows\\system32\\ '))  print (Os.path.normpath (' c://windows\\ system32\\. /temp/')  a= '/users/jieli/test1/\\\a1/\\\\aa.py/. /..‘ Print (Os.path.normpath (a)) print (Os.path.dirname (Os.path.dirname (Os.path.abspath (__file__))) base_dir= Os.path.normpath (Os.path.join (    os.path.abspath (__file__), '.. ', '..    ')) Print (Base_dir)

Seven, sys module

Simulation Progress bar Application

#!/usr/binl/env Python#encoding:utf-8#author:yangleiimport sys,timedef Progress (percent,width=50): #51    if Percent >=:        # print (' \r[%s] 100%% '% (width* ' # '))        percent=100    show_str= (' [%%-%ds] '%width)% (int ( width*percent/100) * ' # ')    print (' \r%s%d%% '% (show_str,percent), file=sys.stdout,flush=true,end= ') #total_size = 1025121recv_size=0while Recv_size < total_size:    time.sleep (0.01) #模拟下载的网络延迟    recv_size+=1024    recv_ Per=int (100*recv_size/total_size)    Progress (recv_per,width=10)

viii. JSON and pickle modules

(1) JSON

Wide Application Platform

#!/usr/binl/env python#encoding:utf-8#author:yangleiimport jsondic={' name ': ' Yanglei ', ' Age ': 23}print (Type ( Json.dumps (DIC))) with open (' A.json ', ' W ') as F:    F.write (Json.dumps (DIC)) with open (' A.json ', ' R ') as F:    data= F.read ()    dic=json.loads (data)    print (dic[' name ') dic={' name ': ' Yanglei ', ' Age ': 23}json.dump (' Dic,open (' B.json ', ' W ')) Print (Json.load (open (' B.json ', ' r ')) [' name ']) with open (' C.json ', ' R ') as F:    Data=f.read ()    #[ null,true,false,1]    eval (data)

(2) Pickle

Valid only for Python

#!/usr/binl/env python#encoding:utf-8#author:yangleiimport pickledic={' name ': ' Yanglei ', ' Age ': 23}print ( Pickle.dumps (DIC)) with open (' D.pkl ', ' WB ') as F:    F.write (Pickle.dumps (DIC)) with open (' d.pkl ', ' RB ') as F:    dic= Pickle.loads (F.read ())    print (dic[' name ') dic={' name ': ' Yanglei ', ' Age ': 23}pickle.dump (Dic,open (' e.pkl ', ' WB ') ) Print (Pickle.load (' e.pkl ', ' RB ')) [' Name ']) def func ():    print (' from Func ') Import Jsonprint (Json.dumps (func )) Import Pickleprint (Pickle.dumps (func)) Pickle.dump (Func,open (' func.pkl ', ' WB ')

Nine, shelve module

Module method

#!/usr/binl/env python#encoding:utf-8#author:yangleiimport Shelvef=shelve.open (R ' sheve.shl ') f[' Yanglei ']={' age ' : ' pwd ': ' 123456 '}f[' Xiaolan ']={' age ': ' pwd ': ' 123456 '}f.close () Obj=shelve.open (R ' SHEVE.SHL ') print (obj[') Yanglei ']) print (obj[' Xiaolan ') obj.close () for i in obj:    print (I,obj[i])

Sixth: Python Foundation _6 built-in functions and common modules (i)