all Python 3Strings (str)function

str.isdecimal

character checks

True if all characters are decimal digits (0–9); stricter than isdigit.

Syntax

s.isdecimal()

Of the trio isdecimal → isdigit → isnumeric this is the narrowest check, and the only one worth trusting before int(): True means every character is a decimal digit (Unicode category Nd) that int() can parse. Signs, dots and spaces are not in that set, so '-5' and ' 12' come back False — for signed or fractional input fall back to try/except ValueError.

Examples

print('123'.isdecimal())  # → True
print('²'.isdecimal())    # → False
print(''.isdecimal())     # → False

See also

Open in the full glossarydocs.python.orgReport an inaccuracy