Module classification:
One, the standard library
1. Time module
a. time和datetime
Timestamp (from 1970 to the present in seconds) and formatted time representation ("2018-6-25 10:12:33")
Timestamp: print(time.time())
time.sleep(3) sleeps for three seconds
time.gmtime(), pass in a timestamp, return UTC standard time, expressed as a tuple (counted from 1970)
time.localtime(), pass in a timestamp, and return the local (UTC+8) time, expressed as a tuple (from 1970)
time.mktime(time.localtime()), converted to timestamp
time.strftime("format", struct_time) is converted to formatted time (time.gmtime and time.localtime are both struct_time)
time.strptime("formatted time string", "format") is the opposite of strftime, converting formatted time into tuple form
Format time string: print(datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S"))
2. Random module
random.random() randomly returns a floating point number between 0 and 1
random.randint(1,10) randomly returns an integer between 1~10
random.randrange(1,10) randomly returns a number between 1-9
random.choice("hello") then returns a value in the sequence
random.sample("sequence",2) randomly take two values from the sequence
random.uniform(1,3) randomly returns a floating point number between 1 and 3
random.shuffle(l) l is a list. Assuming that some numbers are stored in an orderly manner, after executing this sentence, the numbers in l are shuffled, which is equivalent to the shuffle function. After print(l), l is found The order of numbers in has been disrupted
3. os module
os.getcwd() Get the current operating directory
os.chdir("C:\\Users") switch the current path
os.makedirs(r"W:\a\b\c") Recursively create directories
os.removedirs(r"W:\a\b\c") If it is empty, delete the directory recursively (clean up empty folders)
os.rmdir(r"W:\a\b\c") Regardless of whether it is empty or not, only delete the c file
4. Shuil module
shutil.copyfileobj(file1,file2) copies the contents of file1 to file2
shutil.copyfile(file1,file2) is more convenient than the above statement, and the functions performed are the same
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Two, open source modules
Three, custom modules