Re^3: Challenge - Creative Way To Detect Alpha Characters

[ambrus]

No. The isalpha function I gave returns true only for [a-zA-Z] characters, false on numbers, punctation, international letters, or any other character.

It seems to give the same results for me than lc ne uc:

sub isalpha {
    no warnings "numeric";
    my($p) = @_;
    0==++$p;
}
sub hasalpha {
    my($s) = @_;
    isalpha(substr($s, 0, 1, "")) and return 1 while
        length($s);
    return;
};
@t = ("f/2", "-2/", "*+)", "165", "foop", "  A=");
$\=$/; $,=" ";
print grep hasalpha($_), @t;
print grep lc ne uc, @t;

outputs

f/2 foop   A=
f/2 foop   A=

This is because if $p is a non-alnum character in the isalpha function, $p++ converts it to a numeric 0 first, than it increases it to 1, so 0==$p++ is false.