Python re.sub() with dots

Question

I would like to put a space before and after a dot in text but only if its not a part of a date.

So far I have this, and I figured out I have to do something with \D\. but it gives back the letter before the dot not only the dot:

string = re.sub("\.", " . ", string)

For example:

Input text:

1992.01.04 is my birthday.

Required output:

1992.01.04 is my birthday .

There is a space before the end of string dot.

Other question is the same with colon and time,

Input text:

The time is 11:48, reported by: Tom.

Required output:

The time is 11:48, reported by : Tom.

There is a space after text 'reported by' before the colon.

Answer 1

You can use this regex which does a negative look ahead and negative look behind to check if dot/colon is surrounded by digits and replace it with ' \1 '

(?<!\d\d)([.:])(?!\d+)

Demo, https://regex101.com/r/hr6slz/4

This regex works for both colon and dot and as you can replace it by ' \1 '

Answer 2

You need _ positive lookbehind assertion._ (or negative, with \d). Look into https://docs.python.org/3/library/re.html for details.

re.sub("(?<=\D)\.(\D?)", " . ", '1992.01.04 is my birthday.')