def hide_reserve_3(s):
return '*' * (len(s[0])-3) + s[0][-3:]
re.sub(r'\d+', hide_reserve_3, 'User\'s mobile number is 1234567890')
output: "User's mobile number is *******890"
Above I've retrieved from
https://medium.com/towards-data-science/7-useful-tricks-for-python-regex-you-should-know-ec20381e22f2
I just don't quite get why there is a slicing operation in the function. (s[0])
Can someone please explain it to me thoroughly what is going on?
Thanks.
Here is the function with comments:
def hide_reserve_3(s):
return '*' * (len(s[0])-3) + s[0][-3:]
# ^ repeat * length ^ slice for last 3 characters
# of string - 3
So this function builds an output consisting of a string with * repeated the length of the input s minus 3, concatenated with the final 3 digits in s.
The outer call to re.sub will match every number substring in the input and replace it by using the above slicing function.