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passing \n (new line) on stdout throught sys argument
1 answer
I have a problem with passing special characters to python from the command line. This is my script:
# -*- coding: utf-8 -*-
import sys
if __name__ =="__main__":
if len(sys.argv) == 2 :
str = sys.argv[1]
else :
str = '\r\nte st'
print (str)
And these are my test cases:
D:\>testArgv.py "\r\nt est"
\r\nt est
D:\>testArgv.py
te st
I want to know how to pass arguments to python from the command line to archieve a goal like the latter case. Or how I should change my script.
You can use decode with the 'unicode_escape' text encoding from the codecs module to transform a raw string into a typical ol' string:
# -*- coding: utf-8 -*-
import sys
from codecs import decode
if __name__ =="__main__":
if len(sys.argv) == 2:
my_str = decode(sys.argv[1], 'unicode_escape')
# alternatively you transform it to a bytes obj and
# then call decode with:
# my_str = bytes(sys.argv[1], 'utf-8').decode('unicode_escape')
else :
my_str = '\r\nte st'
print (my_str)
The end result is:
im@jim: python3 tt.py "\r\nt est"
t est
This applies to Python 3. In Python 2 str types are pretty ambiguous as to what they represent; as such, they have a decode method of their own which you can use instead. As a result, you could drop the from codecs import decode and just change the line to:
my_str.decode('string_escape')
To get a similar result.
Addendum: Don't use names like str for your variables, they mask names for the built-in types Python has.
