Python file Operations

1. File reading and writing process

1. Open File

2. Write the contents to the file;

3. Close the file

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2. file reading and writing

If the file is small, read () One-time reading is most convenient;

If the file size cannot be determined, the read (size) is called repeatedly

Compare insurance; If it is a configuration file, call ReadLines ()

Binary file, open with ' RB ' mode

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Pattern of 3.open functions

R opens in read mode, navigates to the beginning of the file, the default mode

R+ Open as read-write, locate the beginning of the file, can write content to the file

W is opened in writing, the contents of the file are emptied when the file is opened, and cannot be read

w+ opens in read-write mode, navigates to the file header, and clears the contents of the file when the file is opened

A writes open, navigates to the end of the file, is an append operation, but does not allow read

A + opens in a read-write manner, navigates to the end of the file, and appends the method

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4. Other operations of the file

F.flush () function to write the contents of the buffer to the hard disk

F.seek (offset[,whence]), offset indicates how many bytes are moved, whence is 1 when it moves relative to the current position, and when 2 moves backwards from the end of the file, but not all platforms are supported; The default is 0 to move backward from the beginning of the file

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F.tell () function, which returns the offset of the current file pointer

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5.with syntax

In general, open a file, and after it has been manipulated, explicitly execute xx.close () to close the file. With for operations that need to be turned on and off, the open object can be closed automatically.

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Python file Operations