Python-将字符串转换为命令

Question

I'm currently creating a script that'll loop run a set of Subprocess, and then wait for all the subprocess to finish. I have to add variables in to the subprocess before running them, so I was thinking of writing it as a string, and then converting the string to a command? Would something like that exist?

For example, I have these stringss:

"p1 = subprocess.Popen('python','hello.py')"
"p2 = subprocess.Popen('python','hello2.py')"

How would I execute it to be able to call p1 or p2 later on in the script? (Eg p1.wait())

Answer 1

Using strings is a bad idea, I'd use a list:

options = [('python','hello.py'), ('python','hello2.py')]
for option in options:
    process = subprocess.Popen(option) 
    #do something here

Answer 2

exec("p1 = subprocess.Popen('python','hello.py')")

Note that exec executes statements, while eval evaulates expressions.

But I agree with the other answer that it's better to do this in a different way if you can. One thing you should definitely never do is execute arbitrary strings whose source you don't know, for instance if they could come from a user.