Python file operations

Read and write files

f = open ("Test.txt","R", encoding='Utf-8') data = F.read ()
Print (data) F= Open ("Test.txt","W", encoding='Utf-8'#写入, is the way to create new files, and if there are duplicate names of the files, the old content will be emptied. F.write ("hehe \ n") #\n is a newline character.
F.close () #关闭文件

Append file

f = open ("test.txt","a", encoding='utf-8 ' ) f.write (" oh da ") f.close ()

Read file by line

 #   Cheng  f = open ( " test.txt  " ,  " r  " , Encoding= '  

f = open ("test.txt","R", encoding='utf-8 ' ) for in range (5): #读五行     print(F.readline ()) F.close ( )

Another way ReadLines

First, look at what the ReadLines output looks like.

It will convert the contents of the file into a list.

Next we output what we want.

#the writing of Cheng rubbishf = open ("Test.txt","R", encoding='Utf-8') Count=0 forLineinchf.readlines ():ifCount <= 9:#Remove the first 10 lines        Print(Line.strip ()) Count+ = 1Else: Exit () F.close ()

Note: It's OK to read a small file so that reading a large file requires the file to be stored in memory, which causes the program to die.

Advanced Notation (iterator) #

#Chengf = open ("Test.txt","R", encoding='Utf-8') Count=0 forLineinchF:#because the file pointer does not go backwards, it is also progressive.     ifCount <= 9:        Print(line) Count+ = 1Else: Exit () F.close ()

Python file operations