Coding Challenge
π¬ Question: Given a Python string. How to split the string after the second occurrence of the separator (string or character)? In other words: how to ignore the first separator occurrence when splitting a string?

Here are three examples:
'a-b-c-d-e-f-g-h'
andsep='-'
should be split to['a-b', 'c', 'd', 'e', 'f', 'g', 'h']
'a-b'
andsep='-'
should be split to['a-b']
'helloxxxworldxxxpythonxxxisxxxgreat'
andsep='xxx'
should be split to['helloxxxworld', 'python', 'is', 'great']
Solution
You can split a string after the second occurrence of a given character in three steps:
- First, split the whole string using the separator sep in
s.split(sep)
. - Second, combine the first two elements of the resulting split list using the
sep.join()
method call. - Third, use slicing and list concatenation to create a new result list.
The following code creates a function that takes as input a string s
and a separator string sep
and splits the string at the second occurrence:
def my_split(s, sep): all_split = s.split(sep) return [sep.join(all_split[0:2])] + all_split[2:] print(my_split('a-b-c-d-e-f-g-h', '-')) # ['a-b', 'c', 'd', 'e', 'f', 'g', 'h'] print(my_split('a-b', '-')) # ['a-b'] print(my_split('helloxxxworldxxxpythonxxxisxxxgreat', 'xxx')) # ['helloxxxworld', 'python', 'is', 'great']
The code does multiple things.
First, it creates a list all_split
by splitting the string s
using separator sep
. For example, when using it on string 'a-b-c-d-e-f-g-h'
and sep='-'
, it would return ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h']
.
π Recommended Tutorial: Python String Split
Second, it combines the first two elements using the separator string sep
between them by running sep.join(all_split[0:2])
.
Recommended Tutorials: π
- Python String Join for
sep.join(...)
- Python Slicing for
all_split[0:2]
Third, it puts the result into a list using the square bracket notation, i.e., we get a list with one string element ['a-b']
for our example.
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Fourth, you concatenate this list with the remaining all_split
list, ignoring the first two split results, that are already merged to ignore the first split, by using the slicing expression all_split[2:]
.
In our example, we get ['a-b']
and ['c', 'd', 'e', 'f', 'g', 'h']
that concatenates to ['a-b', 'c', 'd', 'e', 'f', 'g', 'h']
.
π Recommended Tutorials: List Concatenation in Python
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