Python Open Detailed

The mode of opening a file is:

1, R, read-only mode "default".

2, W, write-only mode. "Unreadable, does not exist, is created, the content is deleted"

3, A, append mode. "Readable, non-existent, created, only append content exists"

Second, + means you can read and write a file at the same time

1, R +, can read and write files. "Readable, writable, can be added"

2, w+, write read

3, A + with a

Three, "U" means that when reading the data, \ r \ n \ r \ nthe automatic conversion to \ n (in conjunction with R or r+ mode)

RU

R+u

Four, "B" means processing binary files (such as: FTP send upload ISO image file, Linux can be ignored, Windows processing binary needs to be labeled)

Rb

Wb

Ab

V. Read by character

#read Specify read characters
f = open (' Test.log ', ' R ', encoding= ' utf-8 ')
ret = F.read (2) #按照2个字符读, Python2 is read in 2 bytes.
F.close ()
Print (ret)

VI. Tell

#tell pointer at a byte
f = open (' Test.log ', ' R ', encoding= ' utf-8 ')
Print (F.tell ()) #查看当前指针位置
F.read (2)
Print (F.tell ())
ret = F.read (2) #按照2个字符读, Python2 is read in 2 bytes.
F.close ()

Seven, Seek

#seek
f = open (' Test.log ', ' R ', encoding= ' utf-8 ')
F.seek (1) #指定当前指针位置.
F.read ()
F.close ()
Print (ret)
Eight, F.truncate

File Test.log starts with: ABCDEFG

f = open (' Test.log ', ' r+ ', encoding= ' utf-8 ')
F.seek (3)
F.truncate () #截取光标前面的内容并保存到原文件
F.close ()
The contents of this file change to: ABC

Python Open Detailed