Python path "fifth": Python Basics (20)-modules, serialization, OS modules

Common Module Time Module time.time ()

Import  Time Import datetime Print # returns the timestamp of the current time

Time.ctime ()

Print # Convert timestamp to string format wed Feb 17 11:41:27 2016, the default is the timestamp of the current system time Print # CTime can receive a timestamp as a parameter, returning the string form of the timestamp Wed 10:43:04

Time.gtime ()

Print # Convert timestamp to struct_time format, default is current system timestamp Print (Time.gmtime (Time.time ()-3600))

Time.localtime ()

Print # The same time stamp is converted to struct_time, except that the local time is displayed, Gmtime shows the standard Time (Galini time)

Time.mktime ()

Print # Convert struct_time time format to timestamp

Time.strftime ()

Print (Time.strftime ("%y-%m-%d%h:%m:%s"# converts the struct_time time format into a custom string format

Time.trptime ()

Print (Time.strptime ("2016-02-17""%y-%m-%d"# convert string format to Struct_time format, as opposed to Trftime

Time.asctime ()

Print # Convert struct_time to string form

DateTime module

• Datetime.date: A class that represents a date. Common attributes are year, month, day
• Datetime.time: A class that represents time. Common properties are hour, minute, second, microsecond
• Datetime.datetime: Represents the date time
• Datetime.timedelta: Represents a time interval, that is, the length between two points in time

Datetime.date.today ()

Print # returns the string form of the current date 2016-02-17

Datetime.date.fromtimestamp ()

Print # Converts a timestamp into a date string form 2016-02-16

Datetime.datetime.now ()

Print # returns the time of the string form 2016-02-17 13:53:30.719803 Print # Convert to Struct_time format

Datetime.timedelta ()

Datetime.timedelta () Returns a time interval object, often combined with datetime.datetime.now () to compute time

Print (Datetime.datetime.now ()-Datetime.timedelta (days = 2))

Random module

The random module is primarily used to generate

Random ()

Generate a random number of floating-point types greater than 0 and less than 1

Print # generate a random number of floating-point types greater than 0 and less than 1

Serialization of

Two modules for serialization in Python

• JSON is used to convert between "string" and "Python Basic data Types"
• Pickle for "Python-specific type" and "Python basic data type" to convert between

The JSON module provides four functions: dumps, dump, loads, load

The Pickle module provides four functions: dumps, dump, loads, load

OS Module

Provides an interface to invoke the operating system

>>>ImportOS>>> OS.GETCWD ()#get current working directory, Linux-like pwd command'/data/python/day5'>>> Os.chdir ('..')#Enter a directory, Linux-like CD command>>>OS.GETCWD ()'/data/python'>>> Os.curdir#Get current directory'.'>>> Os.pardir#gets the parent directory of the current directory'..'>>> Os.chdir ('Day5')>>>OS.GETCWD ()'/data/python/day5'>>> Os.makedirs ('Testdir1/testdir2')#recursive creation of directories equivalent to the MKDIR-P command>>> Os.makedirs ('Test_dir1/test_dir2')#recursive creation of directories equivalent to the MKDIR-P command>>> Os.listdir ('.')#displays all the files in the directory equivalent to the Linux ls-a['Test_dir1']>>> Os.removedirs ('Test_dir1/test_dir2')#Delete the multi-level (recursive) directory, note that the directory must be empty, if the directory is empty delete, and recursively to the upper and the directory, if also empty also deleted>>> Os.mkdir ('test2')#Create directory, equivalent to mkdir>>> Os.rmdir ('test2')#Delete directory, equivalent to RM>>> f = open ('Test.txt','W')>>> F.write ('Testline')8>>>f.close ()>>>Os.listdir () ['Testdir2','Test.txt','Testdir1']>>> Os.rename ('Test.txt','New_test.txt')# Renaming>>> Os.stat ('.')#Displays the status of a directory or file, including permissions, etc.Os.stat_result (st_mode=16877, st_ino=786731, st_dev=64784, st_nlink=4, St_uid=0, St_gid=0, st_size=4096, st_atime= 1455695375, st_mtime=1455696066, st_ctime=1455696066)>>> Os.sep#gets the file separator, Linux for/,windows \ \'/'>>> Os.name#returns the platform name, Linux for Posix,win NT'POSIX'>>> Os.linesep#returns system line break, win under \ r \ n'\ n'>>> Os.pathsep#returns the string used to split the file path, under Vin;':'>>> Os.system ('ls')#Execute shell CommandTestdir1 Testdir20>>> Os.environ#Get system Environment variablesEnviron ({'USER':'Root','PATH':'/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin','SHELL':'/bin/bash','HOME':'/root','SHLVL':'1','Histtimeformat':'%... Omit n much better ...>>> Os.path.abspath ('.')#returns the absolute path of the directory'/data/python/day5'>>> Os.path.split ('/data/python/day5')#the path is partitioned into directories and files, and Ganso returns('/data/python','Day5') >>> Os.path.dirname ('/data/python/day5')#return path is also the first element of split'/data/python'>>> Os.path.basename ('/data/python/day5')#The return file name is also the first element of split'Day5'>>> os.path.exists ('/data/python/day5')#determine if a directory or file existsTrue>>> Os.path.isabs ('/data/python/day5')#determine if it is an absolute directory, regardless of whether it exists, and plainly that the string conforms to the absolute path of the specification returns trueTrue>>> Os.path.isabs ('Day5') False>>> Os.path.isabs ('/data/python/day6')# True>>> Os.path.isfile ('/data/python/day5')#determine if it is a fileFalse>>> Os.path.isdir ('/data/python/day5')#determine if it is a directoryTrue>>> Os.path.isdir ('/data/python/day6') False>>> Os.path.join ('/data/python/day6','Test')#Combined Catalog'/data/python/day6/test'>>> Os.path.getatime ('/data/python/day5')#returns the last access time for a file or directory1455695375.9394312>>> Os.path.getmtime ('/data/python/day5')#returns the last modified time of a file or directory1455696066.0034554>>> Os.path.getctime ('/data/python/day5')#returns the creation time of a file or directory1455696066.0034554

Python path "fifth": Python Basics (20)-modules, serialization, OS modules