str.partition() Partition by sep
Last updated: 2026-09-22
str.partition() Partition by sep
str.partition(sep) returns (before, sep, after); if not found, returns (string, '', '').
| Category | String Methods |
|---|---|
| Kind | Built-in Type Method |
| Python Version | all |
📝 Syntax
str.partition(sep)⚙️ Parameters
| sep Required | The separator substring to split at. |
|---|
Returns：tuple. (head, sep, tail); if sep is absent, returns (string, '', '').
Mutates the original：No (returns a new object)
💥 Raises
ValueError— Raised when sep is an empty string.
▶ Example
Edit the code, press Run, and see the result in the output panel:
Output：
('a', '=', 'b=c')
('hello', '', '')💡 Related Cases
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❓ FAQ
QWhat is returned when the separator is not found?
A(original_string, '', ''), without raising an error.
QWhat type does it return?
AIt always returns a 3-tuple (before, sep, after). 'a=b=c'.partition('=') returns ('a', '=', 'b=c'), splitting only at the first occurrence.
QWhat happens when sep is an empty string?
AA ValueError: empty separator is raised.
QWhat is the difference from split()?
Apartition() splits once, returns a 3-tuple, and keeps the separator; split() splits multiple times, returns a list, and drops the separator.
