According to Python docs, perhaps the most important metacharacter in regular expressions is the backslash, \. As in Python string literals, the backslash can be followed by various characters to indicate various special sequences. It’s also used to escape all the metacharacters so you can still match them in patterns; for example, if you need to match a [ or \, you can precede them with a backslash to remove their special meaning: \[ or \\.
The following code highlights the function of backslash in Python regex
Example
import re
result = re.search('\d', '\d')
print result
result = re.search(r'\\d', '\d')
print result.group()Output
This gives the output
None \d