Introduction to Python file processing

Related API:

Folder:

Get the current working directory, that is, the directory path where the current Python script works: os. getcwd()

Returns all file and directory names in the specified directory: os.listdir()

Function is used to delete a file: os.remove()

Delete multiple directories: os.removedirs(r "c:\python")

Check whether the given path is a file: os.path.isfile()

Check whether the given path is a directory: os.path.isdir()

Judge Whether it is an absolute path: os.path.isabs()

Check whether the given path actually exists: os.path.exists()

Return the directory name and file name of a path: os.path.split()

Separate extension: os.path.splitext()

Get path name: os.path.dirname()

Get file name: os.path.basename()

Run shell command: os.system()

Read and set environment variables: os. getenv() and os.putenv()

gives the line terminator used by the current platform: os.linesep Windows uses '\r\n', Linux uses '\n' and Mac uses '\r'

Indicate the platform you are using: os.name For Windows it is 'nt' and for Linux/Unix users it is 'posix'

Rename: os.rename ( old, new)

Create a multi-level directory: os.makedirs(r "c:\python\test")

Create a single directory: os.mkdir(" test”)

Get file attributes: os.stat(file)

Modify file permissions and timestamp: os.chmod(file)

Terminate the current process: os.exit()

Get the file size: os.path.getsize(filename)

File:

fp = open("test.txt",w) Open a file directly. If the file does not exist, create the file

About open mode:

w Open in writing mode,

a Open in append mode (start from EOF, create new file if necessary)

r+ Open in read-write mode

w+ Open in read-write mode (see w)

a+ Open in read-write mode (see a)

rb Open in binary read mode

wb Open in binary write mode (see w)

ab Open in binary append mode (see a)

rb+ Open in binary read-write mode (see r+)

wb+ Open in binary read-write mode (see w+)

ab+ Open in binary read-write mode (see a+)

fp.read([size])                                                                                                                                                                                                                                                                            #([size])               #Read a line, if size is defined, it is possible to return only a part of the line

fp.readlines([size])                                                                                                                                                                                                                                                Return this list. In fact, it is implemented internally by calling readline() in a loop. If the size parameter is provided, size represents the total length of the read content, which means that only a part of the file may be read.

FP.Write (STR)#Write STR into the file, WRITE () will not add a change of lines behind STR FP.Writelines (SEQ)# All contents are written to the file (multiple lines are written at once). This function also just writes faithfully, without adding anything after each line.

fp.close()                   #Close the file. Python will automatically close a file after it is no longer used. However, this function is not guaranteed. It is best to develop the habit of closing it yourself. If a file is operated on after it is closed, a ValueError will be generated.

fp.

()

fp.fileno()                                                                                                                                                                           ‐   ‐ ‐ ‐ ‐                                                                          . )

fp.tell()                                                                                                                                                                                           ‐ ‐ ‐ ‐ ‐ ‐ ‐ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​, and move the file operation flag to the next One line. When a file is used in a statement such as

... in file, the next() function is called to implement traversal.

fp.seek(offset[,whence])             #Move the file operation mark to the offset position. This offset is generally calculated relative to the beginning of the file, and is generally a positive number. But this is not necessarily the case if the whence parameter is provided. whence can be 0 to start the calculation from the beginning, and 1 to use the current position as the origin. 2 means the calculation is performed with the end of the file as the origin. It should be noted that if the file is opened in a or a+ mode, the file operation mark will automatically return to the end of the file every time a write operation is performed. fp.truncate([size])                         #Cut the file to the specified size. The default is to cut to the position of the current file operation mark. If size is larger than the file size, depending on the system, the file may not be changed, the file may be padded to the corresponding size with 0, or some random content may be added.

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