python - How to insert space between alphabet characters and numeric character using regex?

Question

I'm trying to insert space between numeric characters and alphabet character so I can convert numeric character to words like :

Input : 
     subject101
     street45
Output :
     subject 101
     street 45

I tried this one

re.sub('[a-z][d]|[d][a-z]',' ','subject101')

but the output was like this :

subjec 01

How can I do it using python?

Answer 1

Try this Regex:

(?i)(?<=d)(?=[a-z])|(?<=[a-z])(?=d)

Click for Demo

Replace each match with a space

Explanation:

• (?i) - modifier to make the matches case-insensitive
• (?<=d)(?=[a-z]) - finds the position just preceded by a digit and followed by a letter
• | - OR
• (?<=[a-z])(?=d) - finds the position just preceded by a letter and followed by a digit

Code output

import re
regex = r"(?i)(?<=d)(?=[a-z])|(?<=[a-z])(?=d)"
test_str = ("subject101
"
    "     street45")
subst = " "
result = re.sub(regex, subst, test_str, 0)
if result:
    print (result)