1. random module
Introducing the random module, the format is:
import random
1.1 random decimal
Take a random decimal: mathematical calculations.
Print (random.random ()) # decimal taken between 0-1 Print (random.uniform (1,2)) takes a decimal between 1-2 #
1.2 random integer
Take random integers: lottery, lottery has used.
print (random.randint (1,2)) # [1,2] print (random.randrange (1,2)) # 1.2) print (random.randrange (1,200,2)) # 1.2 )
1.3 randomly selected value from the list
Value randomly selected from a list, such as sweepstakes.
l = ['a','b',(1,2),123] print(random.choice(l))print(random.sample(l,2))
1.4 disrupt the order of the list
Disrupt a list order in the list on the basis of the original modified directly, saving space, e.g. shuffling.
random.shuffle(l) print(l)
2. time module
time and time module is mainly used to dealing
Time is introduced into the module, the format is:
import time
Time format:
'2018-8-20' 2018.8.20 'string data type formatted time - posters structured time 1,534,732,642.617272 floating-point data type, the time stamp in s - to the machine calculation of 197,011 0: 0: 0
2.1 Time timestamp
print(time.time())
2.2 Formatting time
print(time.strftime('%Y-%m-%d %H:%M:%S')) # str format timeprint(time.strftime('%y-%m-%d %H:%M:%S')) # str format timeprint(time.strftime('%c'))
2.3 Structure of the time
struct_time = time.localtime() # 北京时间print(struct_time)print(struct_time.tm_mon)
2.4 time stamp to a string
print(time.time()) struct_time = time.localtime(1500000000)# print(time.gmtime(1500000000))ret = time.strftime('%y-%m-%d %H:%M:%S',struct_time)print(ret)
String transfer time stamp 2.5
struct_time = time.strptime('2018-8-8','%Y-%m-%d') print(struct_time)res = time.mktime(struct_time)print(res)
3. sys module
sys is a Python interpreter and dealing
Sys module is introduced, the format is:
import sys
3.1 argv
Print (the sys.argv) # the argv first parameter is the command value of this latter python usr = INPUT ( 'username') pwd = INPUT ( 'password') usr = the sys.argv [. 1] pwd = the sys.argv [ 2] IF usr == 'xhh' and pwd == 'xhh0308': Print ( 'Login successful') the else: Exit ()
3.2 path
Module is the presence of the interpreter is it? Not.
Module should exist on the hard disk,
but when I use the import -> This module into memory only.
A module can be successfully introduced, it all depends on sys.path Here there is no such module is located.
Custom module when importing modules when, still need to focus on sys.path.
3.3 modules
print (sys.modules) # We are the names of all modules into memory: the memory address of the module print (. sys.modules [ 're' ] findall ( '\ d', 'abc126'))
4. os module
Os module is introduced, the format is:
import os
os is the operating system and interactive modules
4.1 os module common method
os.makdirs ( ' dirname1 / dirname2 ' ) may generate a multilayer recursive directory os.removedirs ( ' dirname1 ' ) if the directory is empty, delete, and recursively to the parent directory, should be empty, delete, and so analogy os.mkdir ( ' dirname ' ) to generate a single level directory; is equivalent to the shell dirname mkdir os.rmdir ( ' dirname ' ) empty directory delete a single stage, if the directory is not empty can not be deleted, being given; corresponds to the shell rmdir dirname os.listdir ( ' dirname ' ) lists all the files and subdirectories in the specified directory, including hidden files, and print in a list os.remove () to delete a file os.rename ( " oldname " , " newname " ) weight name the file / directory os.State ( 'path / filename ' ) get the file / directory information os.system ( " bash the Command " ) to run shell commands, displayed directly os.popen ( " bash the Command) .read () run shell commands to get the results os.getcwd () Gets the current working directory that the current directory path python script work os.chdir ( " dirname " ) script to change the current working directory; under the equivalent cd shell os.path os.path.abspath (path) returns the absolute path to the path of standardized os. path.split (path) into the path directory and file name tuple returned os.path.dirname (path) returns the directory path of the fact that the first element os.path.split (path) of os.path. basename (path) returns the last path of the file name. how path to / \ or end, it will return a null value. That os.path.split (path) of the second element os.path.exists (path) if the path exist, return True; if the path does not exist, returns False os.path.isabs (path) if the path is the absolute path, returns True os.path.isfile (path) if the path is a file exists, returns True. Otherwise it returns False os.path.isdir (path) if the path is a directory exists, then return True. Otherwise it returns False os.path.join (path1 [, path2 [, ...]]) will return after a combination of multiple paths parameters before the first absolute path will be ignored os.path.getatime (path) return path points to the last access time of a file or directory os.path.getmtime (path) returns the file or directory path points to the last modification time os.path.getsize (path) return path size
4.2 stat structure
Note: the os.stat ( 'path / filename' ) obtaining the file / directory information of the structure description
stat structure: The st_mode: the inode protection mode st_ino: inode node number. st_dev: inode device resides. st_nlink: inode number of links. st_uid: User ID of the owner. st_gid: group ID of the owner. st_size: common file unit size in bytes; wait for data containing special file. st_atime: Time last accessed. st_mtime: last modification time. st_ctime: report by the operating system's " ctime " . On some systems (such as Unix) is the time of most recent metadata changes, on the other systems (such as Windows) is the creation time (see platform documentation for more information).
Properties 4.3 os module
os.sep output operation system-specific path separator for the next win " \\ " , is the Linux " / " os.linesep output current platform using line terminator, to win the " \ R & lt \ n- " , under Linux as " \ n- " is the character string for dividing a win os.pathsep output file path;, under Linux is: the os.name output string indicating the current use internet. win -> ' NT ' ; Linux-> ' POSIX '