i have the following problem. I want to escape all special characters in a python string.
str='eFEx-x?k=;-'
re.sub("([^a-zA-Z0-9])",r'\\1', str)
'eFEx\\1x\\1k\\1\\1\\1'
str='eFEx-x?k=;-'
re.sub("([^a-zA-Z0-9])",r'\1', str)
'eFEx-x?k=;-'
re.sub("([^a-zA-Z0-9])",r'\\\1', str)
I can't seem to win here. '\1' indicates the special character and i want to add a '\' before this special character. but using \1 removes its special meaning and \\1 also does not help.
Use r'\\\1'. That's a backslash (escaped, so denoted \\) followed by \1.
To verify that this works, try:
str = 'eFEx-x?k=;-'
print re.sub("([^a-zA-Z0-9])",r'\\\1', str)
This prints:
eFEx\-x\?k\=\;\-
which I think is what you want. Don't be confused when the interpreter outputs 'eFEx\\-x\\?k\\=\\;\\-'; the double backslashes are there because the interpreter quotes it output, unless you use print.
Why don't you use re.escape()?
str = 'eFEx-x?k=;-'
re.escape(str)
'eFEx\\-x\\?k\\=\\;\\-'
str.encode('string-escape') might be another possibility, if it's “characters that are special to Python string literals”. Who knows what's “special”?Try adding another backslash:
s = 'eFEx-x?k=;-'
print re.sub("([^a-zA-Z0-9])",r'\\\1', s)
