find the starting character position in a line

hifirock has asked for the wisdom of the Perl Monks concerning the following question:

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Re: find the starting character position in a line by Corion (Patriarch) on Apr 16, 2009 at 07:01 UTC
I recommend reviewing your course notes. You can approach the problem using index, Regular Expressions, or with the following code: `$line = " This is the test line"; $* = 'line'; # prepare Perl for treating 'line' @${} = grep { !m!\s! } split //, reverse (''.$${}); shift @{$} while @{$} > $[ +1; print $line[-1], " is the first character.\n";` [download]	[reply] [d/l]
Re: find the starting character position in a line by linuxer (Curate) on Apr 16, 2009 at 08:47 UTC
`$ perl -wle ' $line = " This is a test."; if ( $line =~ m/(\S)/g ) { print pos($line); } ' 4` [download]	[reply] [d/l]
Re: find the starting character position in a line by dHarry (Abbot) on Apr 16, 2009 at 07:03 UTC
index?	[reply]
Re: find the starting character position in a line by wol (Hermit) on Apr 16, 2009 at 10:23 UTC
The position of the first non-space character is the same as the number of (space) characters preceding it. So: `$line =~ m/^(\s)/; print length $1;` [download] or if you're allergic to line endings: `print length [$line =~ m/^(\s)/]->[0];` [download] -- use JAPH; print JAPH::asString();	[reply] [d/l] [select]
Re: find the starting character position in a line by Anonymous Monk on Apr 16, 2009 at 07:05 UTC
What do you plan on doing with that information? `$line = " This is the test line"; if( $line =~ /(\S)/ ){ # match first non-space character print index($line, $1),"\n"; # find index } __END__` [download] perldoc -f index	[reply] [d/l]
Re: find the starting character position in a line by jwkrahn (Abbot) on Apr 16, 2009 at 15:06 UTC
`$ perl -le' my $line = " This is the test line"; $line =~ /^\s+/ and print $+[ 0 ]; ' 1` [download]	[reply] [d/l]