I originally had problems with the S32 description of string function
index. S32 says that if the substring is not found then a bare Int is
returned which evaluates to false, otherwise an Int with the position
of the first substring match is returned. It goes on to say that one
should not evaluate the result as a number. So my question was, how
does one practically use that information for a substring that starts
at position zero which evaluates as false?
Based on the S32 description, I first tried this to remove a comment
from a data line:
my $str = '# a comment';
my $idx = $str.index('#');
if $index && $index >= 0 {
$str = $str.substr(0, $idx);
}
It didn't work for a comment at position zero but it found one at any
other position or no comment at all. Then I tried this:
if $idx {
$str = $str.substr(0, $idx);
}
Same result as the previous method: it would not report a substring at
position zero.
So what am I doing wrong for finding position zero substrings?
Best,
Tom
P.S. The S32 description I believe should note that the default value
of the index starting position is 0.
