What is the use of the Popen class in python

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Popen class

Popen class of the subprocess module. This class can be used to replace the os.popen function. But the disadvantage of the Popen class is that it is a little more complicated to use because it is too powerful. For example:

Print (subprocess.Popen ("echo Hello World", shell=True, stdout=subprocess.PIPE) .stdout.read ()

This line of code can be used to replace the following code:

Print (os.popen ("echo Hello World") .read ())

A more complex example of the Popen class is as follows:

Import subprocess p = subprocess.Popen ('ls', shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT) for line in p.stdout.readlines (): print (line.decode ("utf-8"). Strip () retval = p.wait ()

This code reads all the lines of the result returned by the ls command through the standard output readlines method and outputs these contents to Console. Finally, use the wait method to wait for the execution of the ls command, and finally end the program.

The advantage of the Popen class over the popen function is that it unifies all the options in the Popen class, rather than requiring four different popen functions to do the job.

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