Re: Finding word either side of a word match

It might be a bit quicker using a regex:

#! perl -slw
use strict;

my $word = 'little';

while( <DATA> ) {
    m[(
        [^ \n]*[^\w\n]*
        (\b\Q$word\E\b)
        [^\w\n]*[^ \n]*
    )]x and print "$2, $., $1";
}
__DATA__
little boy blue come blow on your horn
give a little, take a lot
give a lot, take a little
Mary had a little lamb
Don't belittle the little guy
[download]

Gives:

[14:04:33.30]C:\test>junk4
little, 1, little boy
little, 2, a little, take
little, 3, a little
little, 4, a little lamb
little, 5, the little guy
[download]

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

"Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."

Comment on Re: Finding word either side of a word match Select or Download Code

Replies are listed 'Best First'.
Re^2: Finding word either side of a word match by moritz (Cardinal) on Mar 03, 2008 at 14:21 UTC
I don't think that's quicker, in terms of run time. Quicksilver wants to do it for every word in the file, which means that using a regex to search for it will scale like O(n²) (n being the length of the input file) in time, while the traversal of the files is possible in O(n).	[reply]
Re^3: Finding word either side of a word match by BrowserUk (Patriarch) on Mar 03, 2008 at 14:44 UTC
You're right. I completely misread the question. split seems a likely candidate: `#! perl -slw use strict; while( <DATA> ) { my @words = split /[^a-zA-Z']+/; for ( 0 .. $#words ) { printf "%s, $., %s %s %s\n", $words[ $_ ], $_ ? $words[ $_ -1 ] : '', $words[ $_ ], $_ < $#words ? $words[ $_ + 1 ] : '' ; } } __DATA__ little boy blue come blow on your horn give a little, take a lot give a lot, take a little Mary had a little lamb Don't belittle the little guy` [download] Outputs [14:37:07.78]C:\test>junk4 little, 1, little boy boy, 1, little boy blue blue, 1, boy blue come come, 1, blue come blow blow, 1, come blow on on, 1, blow on your your, 1, on your horn horn, 1, your horn give, 2, give a a, 2, give a little little, 2, a little take take, 2, little take a a, 2, take a lot lot, 2, a lot give, 3, give a a, 3, give a lot lot, 3, a lot take take, 3, lot take a a, 3, take a little little, 3, a little Mary, 4, Mary had had, 4, Mary had a a, 4, had a little little, 4, a little lamb lamb, 4, little lamb Don't, 5, Don't belittle belittle, 5, Don't belittle the the, 5, belittle the little little, 5, the little guy guy, 5, little guy [download] Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. "Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."	[reply] [d/l] [select]