Move substring to front of string-CodePudding

I have a field "Numbers" that can have a value such as:

"01-02-03-04-Zero"

I want to change the substring "Zero" to "00" and move it to the front of the string, so that the result is:

"00-01-02-03-04"

Not all rows contain this "Zero" substring so I only want to perform this on fields that do.

CodePudding user response：

You can use regex. In this approach you can replace Zero with 00 if exist.

import re

def change_Zero(st):
    # If we find '-Zero', we replace all strings with '00' that add to the first part. 
    # with '\1' access to first part
    return re.sub(r"(.*)(-Zero)", r"00-\1", st) 

print(change_Zero("01-02-03-04-Zero"))
print(change_Zero("01-02-03-04-05"))

Output:

00-01-02-03-04
01-02-03-04-05

CodePudding user response：

One way to do it is to split the string to a list, find the indexes where "Zero" is, remove them, and add to "00" to the front of the list. Finally joint the list back to a string.

s = "01-02-03-04-Zero"
s_split = s.split("-")
zero_idxs = [n for n, elem in enumerate(s_split) if elem == "Zero"]

for idx in zero_idxs:
    s_split.pop(idx)

s = "-".join(["00"] * len(zero_idxs)   s_split)

This solution will work for any number of "Zero"s in the string.