Get first word of every line

Question

I need to get every first word of the lines in my $lines. So I'm doing an foreach on every line like this:

foreach ($lines as $n => $line) {

}

But then the next part, I need to grab only the first word. So I did this with exploding on a space like this:

$explode = explode(" ", $line);
echo $explode[0];

But this is very slow when I do it with many lines, is there a better and faster solution then using an explode() ?

You could iterate over each line until you find a space. This will be your word. — Jonatan, Oct 01 '13 at 14:22

score 6 · Accepted Answer · answered Oct 01 '13 at 14:22

6

Yes!

$var = substr( $line, 0, strpos( $line, ' ' ) );

substr() trims a string using start position (0, the beginning) and length: http://php.net/manual/en/function.substr.php

We determine the length by using strpos() to find the first occurrence of the search phrase (in this case, a space): http://php.net/manual/en/function.strpos.php

answered Oct 01 '13 at 14:22

Patrick Moore

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How is this any faster than using `explode`? – Naftali Oct 01 '13 at 14:22
3

It's faster because it stops at the first space instead of finding every space like explode(). – UFL1138 Oct 01 '13 at 14:23
Thanks @SetSailMedia, it works and my loading time was way better! Will accept your answer within a few minutes :) – Oct 01 '13 at 14:26

score 3 · Answer 2 · answered Oct 01 '13 at 14:22

3

Use strpos and substr. Get the index of the first space with strpos and then use that index as the end of your substr. That will save you exploding each line.

answered Oct 01 '13 at 14:22

UFL1138

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score 1 · Answer 3 · answered Oct 01 '13 at 14:24

1

Use the String Token function http://www.w3schools.com/php/func_string_strtok.asp

answered Oct 01 '13 at 14:24

Julian Schaefer

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How is this any better than exploding on a space? – abiessu Oct 01 '13 at 14:25
@tborychowski huh, didnt know that. Found the site via google and some examples where helpful to me in the past. – Julian Schaefer Oct 16 '13 at 14:08
1

@JulianSchaefer That's a common trap: to trust google. It's like going to school for education :-) – Dziad Borowy Oct 16 '13 at 14:10

score 0 · Answer 4 · answered Oct 01 '13 at 14:24

0

Use a regex. This should get the match before first space. (?:^|(?:\.\s))(\w+)

answered Oct 01 '13 at 14:24

dudemanbearpig

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I don't believe that will be any faster than explode. Or will it? – UFL1138 Oct 01 '13 at 14:26
@UFL1138 Its faster because regular expressions, if used correctly, stop as soon as they have the first match and don't operate on the entire string in compare to explode. – dudemanbearpig Oct 01 '13 at 14:30
Still there's a lot of overhead to instantiate the regex engine. At any rate it will certainly not be faster than using strpos and substr. – UFL1138 Oct 01 '13 at 17:54

score 0 · Answer 5 · edited May 23 '17 at 11:50

0

You should try this :

list($firstWord) = explode(" ",trim($line));

see here

edited May 23 '17 at 11:50

Community

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answered Oct 01 '13 at 14:24

devict

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Dziad Borowy · Answer 6 · 2013-10-01T15:15:57.727

0

You can also use explode with the limit:

explode(" ", $line, 1);

Although this is much faster than explode without the limit, it is not as fast as the substr() solution suggested by the user: Set Sail Media.

In my tests with 100K lines, every line having around 10K words:

explode       : 175s
explode+limit : 0s
substr()      : 0s

With 1M lines, every line having around 20K words:

explode       : too long :-)
explode+limit : 12s
substr()      : 0s

edited Oct 01 '13 at 15:15

answered Oct 01 '13 at 14:26

Dziad Borowy

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How about 1M lines each with only about 20 words? – UFL1138 Oct 01 '13 at 17:56

Get first word of every line

6 Answers6