Python 3.7+Byte sequencesfunction

bytes.isascii

bytes — is* checks

Checks that every byte is ASCII (0–127); an empty sequence also gives True.

Syntax

b.isascii(...)

ASCII here means only the 0-127 range, not 'printable text': a null byte, a newline and other control codes all pass. The practical value is the guarantee — a True result means decode('ascii') cannot fail, and any ASCII-compatible encoding yields the same characters. Added in Python 3.7.

Examples

print(b'abc'.isascii())   # → True
print(b'Hi 123!\n'.isascii())   # → True
print(b''.isascii())   # → True
print(b'\x80'.isascii())   # → False
print('привет'.encode().isascii())   # → False

See also

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