Splitting and Joining Strings (split, join)

This lesson covers splitting and joining strings with .split() and .join(), so you can freely manipulate text data like CSV. It's written for anyone searching "Python split join tutorial".

.split(separator) breaks a string apart into a list. Conversely, "separator".join(list) combines a list back into a single string. Both are frequently used when working with CSV-like data. Notice that join() is called on the separator string itself — a slightly different pattern than in some other languages.

The sample code splits a comma-separated string, csv, into a list called fruits using .split(","), then rebuilds it into a string using a different separator (a slash) with " / ".join(fruits). Combining these two lets you freely transform text data — swapping delimiters, trimming extra whitespace, and more.

A common beginner mistake is getting the calling convention for .join() backwards. It's written as "separator".join(list), not list.join("separator") — this can feel unintuitive at first. It's a technique that comes up constantly in data-preprocessing work, so it's worth memorizing this order.

Getting the separator right matters especially when working with Japanese or other non-ASCII text data. Reading files, processing API responses, parsing a comma-separated list of tags from a form — split and join together show up in nearly every situation involving text data.