python3.x file Operations

The mode of opening the file is:
1. Read-only mode (default)
2. Write-only mode (unreadable, not present, created, overwrite if present)
3. Append mode (readable, non-existent, create, only append content if present)

"+" means that you can read and write to a file:
1. r+ can read and write files (readable, writable, can be appended)
2. w+ Write Read
3. A + Append

"U" means that the \ r \ n \ r \ \ \ \ \ \ \ \ \ \ \ \ \ r/N (r+ mode) can be converted automatically when reading
Because the line break for the Windows system is \ n for the \r\n,linux system, plus u can automatically convert \ r \ n
1. RU
2. R+u

"B" means processing binary files
1.rb
2.wb
3.ab

#Coding:utf-8#opening File open ()f = open ('Test.txt','r+')#or with open () after this method operation is completed, the close () does not need to be closed automaticallyWith open ('Test.txt','R') as F:f.read ()#Close Filef = open ('Test.txt','r+', encoding='Utf-8') ret=F.read ()Print(ret) f.close ()#reads the contents of the file (you can specify each character read)f = open ('Test.txt','r+', encoding='Utf-8') ret= F.read (8)Print(ret)#read data (can specify number of characters to read), Save as List displayf = open ('Test.txt','r+', encoding='Utf-8') ret=F.readlines ()Print(ret) f.close ()#reading a row of dataf = open ('Test.txt','r+', encoding='Utf-8') ret=F.readline ()Print(ret) f.close ()#Write file The write () parameter is a stringf = open ('Test.txt','A +', encoding='Utf-8') F.write ("ABC") ret=F.read ()Print(ret) f.close ()#write to file, Writelines () parameter is a sequence, such as a list, it will iterate to help you write to the filef = open ('Test.txt','A +', encoding='Utf-8') F.writelines (["AA","BB","cc"]) ret=F.read ()Print(ret) f.close ()#determine if the file is a unified TTY devicef = open ('Test.txt','r+', encoding='Utf-8') ret=F.isatty ()Print(ret)#Falsef.close ()#determine if it is readable (non-readable, "No such file or directory:")f = open ('Test.txt','r+', encoding='Utf-8') ret=f.readable ()Print(ret)#Truef.close ()#specify the position of the pointer in the filef = open ('Test.txt','r+', encoding='Utf-8') ret= F.read (8)#Read 8 characters FirstPrint(ret) f.seek (0)#then move the pointer to the beginning of the fileret = F.read (8)#after re-readingPrint(ret) f.close ()#Get pointer positionf = open ('Test.txt','r+', encoding='Utf-8') ret= F.read (8)#Read 8 characters FirstPrint("Pointer position:%s"%f.tell ())#view current pointer positionPrint(ret) f.seek (0)#Reset specified to start bitPrint("Pointer position:%s"%f.tell ())#when viewing the pointer positionf.close ()#truncate file data, preserving only specified previous data (specified number of bytes)f = open ('Test.txt','r+', encoding='Utf-8') F.truncate (8)#The file retains only the first 8 bytes of data, and all the data behind the file is deleted.RET =F.read ()Print(ret) f.close ()#File DescriptorF.fileno ()#flush File Internal buffersF.flush ()

python3.x file Operations