Re: Regex Question

[kcott]

in reply to Regex Question

G'day shealyw2,

index is another option:

Update: Oops! Left off the POSITION (index STR,SUBSTR,POSITION). Thanks, Ratazong. Here's an improved version.

$ perl -Mstrict -Mwarnings -E '
my $x = "abc";
say $x if index($x, "a", 2) == 2;
my $y = "cba";
say $y if index($y, "a", 2) == 2;
my $z = "aba";
say $z if index($z, "a", 2) == 2;
'
cba
aba

$ perl -Mstrict -Mwarnings -E '
my $x = "abc";
say $x if index($x, "a") == 2;
my $y = "cba";
say $y if index($y, "a") == 2;
'
cba

Note: index is based at zero (1st char = 0; 3rd char = 2)

[Ratazong]

Your index won't work in case there is an a before the third position, e.g. in the string aba. If you (really) want to use index, use the 3-argument-form instead:

$x = "aba";
print "$x\n" if index($x, "a", 2) == 2;

HTH, Rata

[kcott]

++ Thanks Ratazong. You're absolutely correct. I've updated my node.