The use of the open function in Python

Use the following:

Name = open (' Errname.txt ', ' W ')
Name.readline ()
Name.close ()

　　

1, look at the first line of code

Used to access the files stored on the disk, can be read and write operations, such as the "W" in the above example, this is the Errname.txt this file read operation

For example:

W: Open in write mode

A: Open in append mode

r+: Open in read-write mode

w+: Open in read-write mode

RB: Open in binary read mode

WB: Open in binary write mode

AB: Open in binary append mode

rb+: Open in binary read/write mode

wb+: Open in binary read - write mode

ab+: Open in binary append mode

2. Let's look at the second line in the previous example:

1) First look at the usage and differences of ReadLine and ReadLines:

>>> name = open (' Test.txt ', ' r ') >>> username = name.readline () >>> username ' devilf\n ' > >> username = name.readlines () >>> username[' gy\n ', ' tom\n ', ' lisa\n ', ' lebron\n ', ' Kobe ']

　　

As you can see, ReadLine reads only one line of content, while ReadLines reads the contents of the file row by line

But we see that the username list of the output is not a normal list with a \ n newline character, so we need to remove it:

>>> username = [Line.strip (' \ n ') for line in Name.readlines ()]>>> username[' Devilf ', ' Gy ', ' Tom ', ' Lisa ', ' LeBron ', ' Kobe ']

　　

3, the third line

In fact, after the completion of the above operation, a way to close the file, needless to say

The following is a formal explanation of the use of the open () function

One, write the file

1) write in W mode

>>> f = open (' 1.txt ', ' W ') >>> f.write (' This is a test ') 14>>> f.close () >>> g = open (' 1. TXT ', ' r ') >>> G.readline () ' This is a test '

　　

2) write in Append mode

>>> f = open ('1.txt','a')>>> F.write ('2017/1208')9>>>f.close ()>>> f = open ('1.txt','R')>>> g =F.readline ()>>>g'This is a test2017/1208'

The use of the open function in Python