str.find() Find substring position
Last updated: 2026-09-22
str.find() Find substring position
str.find(sub[, start[, end]]) returns the lowest index where sub is found, or -1 if not found.
| Category | String Methods |
|---|---|
| Kind | Built-in Type Method |
| Python Version | all |
📝 Syntax
str.find(sub[, start[, end]])⚙️ Parameters
| sub Required | The substring to search for. |
|---|---|
| start Optional | Start index of the range (inclusive); None means the beginning.（Default：None） |
| end Optional | End index of the range (exclusive); None means the end.（Default：None） |
Returns：int. The lowest index where sub is found, or -1 if not found.
Mutates the original：No (returns a new object)
▶ Example
Edit the code, press Run, and see the result in the output panel:
Output：
2
-1💡 Related Cases
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❓ FAQ
QDoes find() raise an exception when the substring is not found?
ANo. This is its biggest difference from index(): find() returns -1 when not found. Prefer find() when you are not sure the substring exists.
QHow should I choose between find() and index()?
AUse find() when you only want to know "does it exist and where" (returns -1 without error); use index() when it must exist and not finding it is a bug (raises ValueError).
QHow do I find the position of the second occurrence?
AUse the start parameter to skip the first one: 'banana'.find('a', 2) starts searching from index 2 and returns 3. To find the last occurrence use rfind().
QWhat does find('') with an empty substring return?
AIt returns 0 (or the value of the start parameter), because an empty substring matches at any position.
