str.isidentifier() Valid identifier
Last updated: 2026-09-22
str.isidentifier() Valid identifier
str.isidentifier() returns True if the string is a valid Python identifier.
| Category | String Methods |
|---|---|
| Kind | Built-in Type Method |
| Python Version | all |
📝 Syntax
str.isidentifier()Returns：bool. True if the string is a valid Python identifier.
Mutates the original：No (returns a new object)
▶ Example
Edit the code, press Run, and see the result in the output panel:
Output：
True
False
True💡 Related Cases
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❓ FAQ
QWhat does isidentifier() check?
AWhether the string is a valid Python identifier (usable as a variable/function name). 'foo_bar'.isidentifier() is True, '123abc'.isidentifier() is False.
QDo keywords count as valid identifiers?
A'if'.isidentifier() returns True, but if is a Python keyword and cannot be used as a variable name. You must also exclude keywords with keyword.iskeyword('if').
QCan Chinese be an identifier?
AYes. Python 3 supports Unicode identifiers: '名字'.isidentifier() returns True.
