Working with files in Python

Open File Mode process:

Open ----- edit ------ Close the elephant How to put into the refrigerator, do not tube how big, how to put, it is possible that the refrigerator is very large, the elephant is very small, directly open the refrigerator, into the refrigerator, close the refrigerator, haha, the program in the following way:

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A in python represents append, equivalent to the >> in Linux

RB WB AB represents both binary files txt py text files without adding b.

r+ can, but the file does not exist it will not do any processing.

w+ can read and write, if the file does not exist to create, if it is overwritten.

A + can be read and written, if the file is not created and appended at the end.

F.read (1): One value per read f , if f.read () does not add parameters, then once read, re-read is ""

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Create a file and write

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Open by default with R , when only need to read the time can not add r

[email protected] ~]# cat du.py

f = open ("A.txt")

b = F.read ()

Print (b)---- here is the contents of the call to read and cannot be written directly to print B

F.close

[Email protected] ~]#

File copy process and case:

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when a file is copied, it is automatically added with a name and the word "duplicate"

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ReadLine read Only one line, read the result is a string,readlines Read all the lines, read the result is in the list.

How to read large files:

ReadLine It's not a big line, and it's possible that all content without a newline character on one line cannot be used readline readlines read and while loop, then through read 0 when you exit, the case is as follows:

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positioning read/write:F.read ()represents theFread at the beginning of the file and use the pointer if you want to start reading from somewhere elseSeek(,x),asx=0represents the beginning of a file,x=1represents the position at this time,x=2represents the end of a file. F.seek (2,0)represents a two-character move from the beginning to the right. Read the contents of the file to be usedSeek(0,0) Pull it back,Python3negative movement is not supported, otherwise the file needs to be closed and reopened.

F.tell: To get the file where the seek pointer is, as follows:

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common actions for files: by importing import OS, then os.rename ("a.txt"," B.txt") renamed a.txt to b.txt.

Common actions for folders: os.mkdir("Weipeng"), create a directory folder named Weipeng.

OS.GETCWD (): Gets the current directory structure, which is also the default directory, like pwdin linux , of course in py The path can also be modified by means of the open () file as follows:

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To change the directory creation file:

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It is important to get all the files under the current path:

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Batch rename:

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Working with files in Python