Pass in string as argument without it being treated as raw

Question

I want to pass in a string to my python script which contains escape sequences such as: \x00 or \t, and spaces.
However when I pass in my string as:

some string\x00 more \tstring

python treats my string as a raw string and when I print that string from inside the script, it prints the string literally and it does not treat the \ as an escape sequence.
i.e. it prints exactly the string above.

UPDATE:(AGAIN)
I'm using python 2.7.5 to reproduce, create a script, lets call it myscript.py:

import sys
print(sys.argv[1])

now save it and call it from the windows command prompt as such:

c:\Python27\python.exe myscript.py "abcd \x00 abcd"

the result I get is:

> 'abcd \x00 abcd'

P.S in my actual script, I am using option parser, but both have the same effect. Maybe there is a parameter I can set for option parser to handle escape sequences?

Are you literally `print`ing it, or are you just looking at the return value of your function in a console? — Blender, Jul 03 '13 at 02:44
yeah becuase in IDLE i do `print "some string\x00 more \tstring"` and it works just fine — Serial, Jul 03 '13 at 02:46
Can you show a reproducible example of your function? (You can try cutting out everything not related) — David Robinson, Jul 03 '13 at 02:48
no Im passing it in as an argument. so c:\MyScript.py "abc\x00abc". then inside the script I print args[0], and I get abc\x00abc as my output — Siavash, Jul 03 '13 at 02:49
does print(args[0].decode('string-escape')) solve the issue? edited based on your edit. — John Faulkner, Jul 03 '13 at 02:55
Yes, you want John Faulkner's `decode()` method. John, you should post that as an answer! — kindall, Jul 03 '13 at 03:09
@JohnFaulkner it did work! but I had to do s = sys.argv[1] s.decode('string-escape'). for some reason it doesnt like sys.srgv[1].decode() — Siavash, Jul 03 '13 at 03:19
myscript.py contains: import sys print(sys.argv[1].decode('string-escape')) result abcd abcd — John Faulkner, Jul 03 '13 at 03:27
@JohnFaulkner Please put in your solution as an answer to this issue so you can get credit :) — Siavash, Jul 03 '13 at 03:40

score 7 · Accepted Answer · edited May 23 '17 at 12:25

7

The string you receive in sys.argv[1] is exactly what you typed on the command line. Its backslash sequences are left intact, not interpreted.

To interpret them, follow this answer: basically use .decode('string_escape').

edited May 23 '17 at 12:25

Community

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answered Jul 03 '13 at 02:55

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score 6 · Answer 2 · answered Jul 03 '13 at 03:29

6

myscript.py contains:

import sys
print(sys.argv[1].decode('string-escape'))

result abcd abcd

answered Jul 03 '13 at 03:29

John Faulkner

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score 1 · Answer 3 · edited May 23 '17 at 12:17

I don't know that you can parse entire strings without writing a custom parser but optparse supports sending inputs in different formats (hexidecimal, binary, etc).

from optparse import OptionParser
parser = OptionParser()
parser.add_option("-n", type="int", dest="num")

options, args = parser.parse_args()

print options

then when you run

C:\Users\John\Desktop\script.py -n 0b10

you get an output of

{'num': 2}

The reason I say you'll have to impletement a custom parser to make this work is because it isn't Python the changes the input but rather it is something the shell does. Python might have a built in module to handle this but I am not aware of it if it exists.

ok you are the first to understand my problem. This is the right track, but my issue is I need tp pass in a long string that contains \x00 in a few spots. I dont want to pass in the whole string as int values. — Siavash, Jul 03 '13 at 03:05

Pass in string as argument without it being treated as raw

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