Matching first letter of word - regex

Question

I want to match the first letter of a word in one string to another with the similar letter. In this example the letter H:
25HB matches to HC
I am using the match operator shown below:
my ($match) = ( $value =~ m/^d(\w)/ );
to not match the digit, but the first matching word character. How could I correct this?

Answer 1

That regex doesn't do what you think it does:
m/^d(\w)/
Matches 'start of line' - letter d then a single word character.
You may want:
m/^\d+(\w)/
Which will then match one or more digits from the start of line, and grab the first word character after that.
E.g.:
my $string = '25HC';
my ( $match ) =( $string =~ m/^\d+(\w)/ );
print $match,"\n";
Prints H

Answer 2

You are not clear about what you want. If you want to match the first letter in a string to the same letter later in the string:
m{
( # start a capture
[[:alpha:]] # match a single letter
) # end of capture
.*? # skip minimum number of any character
\1 # match the captured letter
}msx; # /m means multilines, /s means . matches newlines, /x means ignore whitespace in pattern
See perldoc perlre for more details.
Addendum:
If by word, you mean any alphanumeric sequence, this may be closer to what you want:
m{
\b # match a word boundary (start or end of a word)
\d* # greedy match any digits
( # start a capture
[[:alpha:]] # match a single letter
) # end of capture
.*? # skip minimum number of any character
\b # match a word boundary (start or end of a word)
\d* # greedy match any digits
\1 # match the captured letter
}msx; # /m means multilines, /s means . matches newlines, /x means ignore whitespace in pattern

Answer 3

You could try ^.*?([A-Za-z]).
The following code returns:
ITEM: 22hb
MATCH: h
ITEM: 33HB
MATCH: H
ITEM: 3333
MATCH:
ITEM: 43 H
MATCH: H
ITEM: HB33
MATCH: H
Script.
#!/usr/bin/perl
my #array = ('22hb','33HB','3333','43 H','HB33');
for my $item (#array) {
my $match = $1 if $item =~ /^.*?([A-Za-z])/;
print "ITEM: $item \nMATCH: $match\n\n";
}

Answer 4

I believe this is what you are looking for:
(If you can provide more clear example of what you are looking for we may be able to help you better)
The following code takes two strings and finds the first non-digit character common in both the strings:
my $string1 = '25HB';
my $string2 = 'HC';
#strip all digits
$string1 =~ s/\d//g;
foreach my $alpha (split //, $string1) {
# for each non-digit check if we find a match
if ($string2 =~ /$alpha/) {
print "First matching non-numeric character: $alpha\n";
exit;
}
}