How to split a string by a substring without white spaces, while keeping its original white spaces?

Question

I am looking for a way to split a string with white spaces (this includes spaces, \n, \t) by a target phrase that has its white spaces removed. This should be able to be done for both before and after the target phrase. It is also necessary that I keep the original string with its white spaces.

As there can be n-th occurrence of the target phrase, I am only looking to split by the first occurrence and getting the characters before it, and split by the last occurrence and getting the characters after it.

For example:

str = 'This is a test string for my test string example only.'
target_phrase = 'teststring'

Intended output:

('This is a', 'test string for my test string example only.) #Split by target phrase and getting characters prior to it
('This is a test string for my test string', 'example only.') #Split by target phrase and getting characters after it

emphasized text

Any hints gratefully received.

Answer 1

Is this acceptable (it doesn't bother to handle the case when the target phrase is not found):

# Splits str at the first occurrence of targ, ignoring spaces in both.
# Returns tuple of substrings produced by the split.
def my_split(str, targ):
    idx = str.replace(' ', '').index(targ)

    # Next, in the original string that has spaces,
    # we count the number of spaces and non-spaces, until
    # the number of non-spaces reaches idx. When that happens,
    # it means we have reached the split-point in the original
    # string that has spaces.
    non_space = 0
    space = 0
    while (non_space < idx) and ((non_space+space) < len(str)):
        if str[space+non_space] == ' ':
            space += 1
        else:
            non_space += 1
    if (space + non_space):
        return (str[:space+non_space], str[1+space+non_space:])
    else:
        return ('', str)

Usage:

print (my_split(str, target_phrase))
print (tuple(s[::-1] for s in my_split(str[::-1], target_phrase[::-1]))[::-1])

Output:

('This is a', 'test string for my test string example only.')
('This is a test string for my test string', 'example only.')