issue while matching special char '\' in regular expression using '\\'

Question

I have very simple python script to match some special characters like -,+,-,. But Im not getting expected result while using regex \ to match a single '\' char.

import re
pat = r'[-+*\\]'
text = 'fdkjdfk\sdsdd'
if re.search(pat,text):
   print re.search(pat,text).group()
else:
   print "not found"

On running above code , it prints 'not found' It seems I am doing some mistake here , any help appreciated !!!

Answer 1

\ is an escape character.

Try escaping it:

text = 'fdkjdfk\\sdsdd' 

Answer 2

Here was the main program (here I am filtering some simple math operators from text) where I got error 1st time. And Im still getting 'not found' in this example. Here in txt I have used '\' char but it is not getting picked by regex.

import re
pat = r'(\d+\.?\d*)([+*\/\\-](\d+\.?\d*)){1,}=\d+\.?\d*'
txt ='djhdf 4*5+9\3=22 fdf'
if re.search(pat,txt):
        print re.search(pat,txt).group()
else:
        print "not found"

Please check if any1 able to figure down the issue. Thanks for time !!!