Do you know the common built-in modules of python?

(coll.) fail (a student)importWhen a module，Do three things automatically：
1. Run through all the code in the module（Ensure that this module does not havebug）
2. Generate a namespace，This name is the same as the module name
3. Let the running program connect to the namespace，Subsequently, you can use the variables in the module/function (math.)
pythonSelf-contained variables in the file：__name__，in the event thatpyThe file is run as a program，__name__ = 'main'，in the event that以模块的方式运行，__name__ = filename

import time
(2) # Program pause in seconds
# Get timestamp
print(())
# Formatted output time
print(('%Y-%m-%d %H:%M:%S'))

import sys
# Get environment variables
print()
print()
print()

import random
# Generate a (0,1) random number
print('%.3f' % ())
print((1,100))
# Randomly take a value from the sequence
li = [1,2,3,4]
c = (li)
print(c)
# Disrupt the ordering of a list
(li)
print(li)

import os
# Get current file location pwd
print(())
# Create a new folder
('aaa')
 # Get the operating system's file separator