Python OS module important points of knowledge

Python OS module important points of knowledge

This is very important, mainly about the file path, I have stepped on a lot of pits, today summed up, convenient to avoid the path associated with the various pits!

1, first we want to get all the folders under a folder and files ( not including files in subfolders)

Lists = Os.listdir (Path)

2, want to get all the folders under a folder (Path) and files (including files within subfolders)

def Listdir (path):      for inch Os.listdir (path):         = os.path.join (path, filename        )if  (os.path.isfile (filename)):            Print  Pathname        Else:            listdir (pathname)

3, get the parent directory folder:

C:\test    getpath.py    \sub         sub_path.py

For example, in the sub_path.py file of this code Os.path.abspath (Os.path.dirname (__file__)) can get the absolute path of the \sub\ directory

For example, in the sub_path.py file of this code Os.path.abspath (os.path.dirname (os.path.dirname (__file__))) You can get the absolute path to the \test\ directory

4, get the current directory and the parent directory

└──folder    ├──data    │   └──data.txt    └──test        └──test.py

Print '* * * Get current directory * * *'PrintOS.GETCWD ()PrintOs.path.abspath (Os.path.dirname (__file__))Print '* * * Get Parent Directory * * *'PrintOs.path.abspath (Os.path.dirname (Os.path.dirname (__file__)))PrintOs.path.abspath (Os.path.dirname (OS.GETCWD ()))PrintOs.path.abspath (Os.path.join (OS.GETCWD (),".."))Print '* * * Get Upper Parent Directory * * *'PrintOs.path.abspath (Os.path.join (OS.GETCWD (),".. /.."))Get current directory ***/workspace/demo/folder/Test/workspace/demo/folder/TestGet Parent Directory ***/workspace/demo/folder/workspace/demo/folder/workspace/demo/folderGet Upper Parent Directory ***/workspace/demo

In addition

# CurDir  indicates that the current folder print(os.curdir)#Pardir  represents the previous folder print (Os.pardir)

5, how to get the path of the called file when calling a file from another directory

C:\test    getpath.py    \sub         sub_path.py

For example, there is a directory named sub under the C:\test directory, C:\test directory under the Getpath.py,sub directory has sub_path.py,getpath.py call sub_path.py; we are in C: \ Test to execute the getpath.py.

If we use sys.path[0 in sub_path.py, we actually get the directory path "C:\test" where the getpath.py is located, because the Python virtual machine is executed from the beginning of the getpath.py.

If you want to get the path to the sub_path.py, you get this:

Os.path.split (Os.path.realpath (__file__)) [0]

Although __file__ is the full path of the. py file, this variable sometimes returns a relative path, sometimes an absolute path, so it is also handled with the Os.path.realpath () function.

In this case, the Os.path.realpath (__file__) output is "C:\test\sub\sub_path.py", while Os.path.split (Os.path.realpath (__file__)) [0] The output is "C:\test\sub".

In short, for example, the difference between OS.GETCWD (), sys.path[0] (sys.argv[0]) and __file__ is this:

Assume that the directory structure is:

C:\test  |  [dir] GetPath    |    [File] path.py    [dir] Sub      |      [File] sub_path.py

Then we execute the python getpath/path.py below the C:\test, at which point the values corresponding to each usage in sub_path.py are actually:

OS.GETCWD () "C:\test", which takes the starting execution directory

Sys.path[0] or sys.argv[0] "C:\test\getpath", which is the directory where the script was executed initially

Os.path.split (Os.path.realpath (__file__)) [0] "C:\test\getpath\sub", which is the directory where __file__ files sub_path.py

Python OS module important points of knowledge