Szathmáry László honlapja @ DEIK | DLang / Is every character a digit?

See also:

(1) isDigit() with all()
def main(): good = "2025" bad = "20xx25" print(good.isdigit()) # True print(bad.isdigit()) # False	import std.stdio; import std.ascii; // isDigit() import std.algorithm.searching; // all() void main() { string good = "2025"; string bad = "20xx25"; bool v1 = good.all!(isDigit); // true writeln(v1); bool v2 = bad.all!(c => c.isDigit); // false writeln(v2); }

How all() works: it checks if the predicate is true for every element.

Of course, any() also exists. It checks if the predicate is true for any (at least one) element.