Python outputs string with newline character from external C program call

Question

This is my first question, any feedback would be amazing.

I am calling a C program from Python3 and the string captured by my variable prints out the newline characters instead of processing a newline character.

Want this: hello world

I get: b'hello\nworld'

I have this c program called find.c:

    int main(int argc, char *argv[]){

        printf("%s:\n%s\n\n",argv[1],argv[2]);
        return 0;
    }

Executed/Ran/Processed by Python3:

    import sys
    import subprocess

    user = sys.argv[1]
    item = sys.argv[2]

    out = subprocess.check_output(["./find", user, item])
    print(out)

Once again, the string "out" contains the "\n" instead of treating it like a new line.

I've tried adding: universal_newlines=True and end="" to check_out() with no luck.

I've tried using Popen() and call() and they both still keep the "\n".

As a last note: I am outputting this string to a textarea in html. And yes I know the b'' is not actually part of the string.

Cheers!

boisterousk · Accepted Answer · 2017-05-16 03:52:38Z

1

EHHHH, I figured it out. For anyone interested I did the following:

    print(subprocess.check_output(["./find",user,item],universal_newlines=True))

I didn't actually try using universal_newlines=True exclusively.

Look at that my first accepted answer as well!

answered May 16, 2017 at 3:52

boisterousk

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Mike Tung · Accepted Answer · 2017-05-16 03:52:14Z

0

In your out you need to strip the carriage return and new lines.

import sys
import subprocess

user = sys.argv[1]
item = sys.argv[2]

out = check_output(["./find", user, item]).strip()
print(out)

answered May 16, 2017 at 3:52

Mike Tung

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1 Comment

boisterousk Over a year ago

Hey, thanks for the quick response! However, there was no output in the textarea html, I did however solve it. See my answer, cheers!

user79854 · Accepted Answer · 2017-05-16 03:54:30Z

0

try this. subprocess is returning a byte string, you want to print it as ascii characters.

print(out.decode('ascii'))

answered May 16, 2017 at 3:54

user79854

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