String manipulation

Enables splitting a string into a list of substrings based on a delimiter

Data parsing: separating CSV fields from a line Log processing: breaking log entries on a space delimiter User input handling: parsing command arguments separated by commas

Python scripts that process text data, such as data‑cleaning pipelines, web‑scraping utilities, configuration file parsers, and command‑line tools

string.split(sep)

... .split(...)

string: str, sep: str

• strip() join() replace() lower() upper()

• str.partition() – splits once into three parts
• useful when you need the part before and after the first delimiter re.split() – uses regular expressions for complex delimiters
• at the cost of regex overhead

Using an empty string as the delimiter, which splits the string into individual characters instead of the intended tokens Assuming `split` mutates the original string; it returns a new list and leaves the original unchanged Passing a non‑string separator (e.g., an integer), causing a TypeError Expecting `split` to discard empty substrings when the delimiter appears at the start or end, but it returns empty strings in those positions

str.partition() – returns exactly three parts (before, separator, after) rather than an arbitrary list re.split() – allows regex patterns for splitting, offering more flexibility str.splitlines() – splits on line boundaries instead of arbitrary delimiters

Coming from JavaScript: using `split` on `null` or `undefined` strings raises a runtime error – ensure the variable is a valid string in Python

• str.split
• str.rsplit
• str.partition
• str.splitlines

Do not use `split` on data where the delimiter may appear inside quoted fields (e.g., CSV with commas inside quotes) – a CSV parser is required Performance: runs in O(n) time and creates a new list, so large inputs can increase memory usage Edge case: consecutive delimiters produce empty strings in the result, which may need filtering

Allows rapid tokenisation of input data, making downstream parsing, validation, and transformation straightforward and less error‑prone

Splitting a sentence is like cutting a loaf of bread into slices with a knife – each slice is a piece of the original loaf.

If `sep` is omitted or set to `None`, `split` defaults to splitting on any whitespace and discards leading/trailing whitespace