How to get specific array element?

Question

Say I have the following array of strings:

$data_array = array("the dog is hairy", "cats like treats", "my mouse is tired");

I want to write a function that will extract an element from the array based on whether it contains another string.

For example, if the array element contains the string "dog" i want to return the string "the dog is hairy" for use elsewhere.

I tried using a foreach loop but it didn't work:

foreach ($data_array as $sentence){
    if (stripos($sentence, "dog")){
        echo $sentence;
    }
}

What is the best way to go about this?

And as @AurelioDeRosa points out, you're best checking for a non-false value since 0 could be interpreted as a falsy value. — Jared Farrish
– Jared Farrish, Commented Oct 9, 2011 at 0:42

Aurelio De Rosa · Accepted Answer · 2011-10-09 00:40:03Z

2

If you want to use stripos this is the code:

   $data_array = array("the dog is hairy", "cats like treats", "my mouse is tired");
   foreach($data_array as $value)
   {
      if (stripos($value, 'dog') !== FALSE)
         echo $value;
   }

answered Oct 9, 2011 at 0:40

Aurelio De Rosa

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1 Comment

Racooon Over a year ago

no need to use foreach or any loop process to do it. Check my example.

genesis · Accepted Answer · 2011-10-09 00:54:54Z

2

It works fine for me.

http://sandbox.phpcode.eu/g/064bf

<?php 
$data_array = array("the dog is hairy", "cats like treats", "my mouse is tired"); 
foreach($data_array as $data){ 
    if (false !== stripos($data, "dog")){ 
        echo $data; 
    } 
}

edited Oct 9, 2011 at 0:54

answered Oct 9, 2011 at 0:39

genesis

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1 Comment

Jared Farrish Over a year ago

The third sentence (about using an appropriate variable for stripos()). The OP doesn't seem to suggest this was a problem.

Clive · Accepted Answer · 2011-10-09 00:37:47Z

1

foreach ($data_array as $val) {
  if (strstr($val, 'dog')) {
    echo $val;
  }
}

answered Oct 9, 2011 at 0:37

Clive

1

1 Comment

MikeJerome Over a year ago

Sorry I just edited my question. I tried that and it didn't work for some reason.

Racooon · Accepted Answer · 2011-10-09 01:28:45Z

0

You can use this example:

$f_array = preg_grep('/dog/i', $data_array);

edited Oct 9, 2011 at 1:28

answered Oct 9, 2011 at 0:55

Racooon

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Comments

Ilmari Karonen · Accepted Answer · 2011-10-09 00:56:11Z

-1

You could also use preg_grep():

$found_array = preg_grep( '/dog/i', $data_array );

Edit: Added /i switch for case-insensitive matching.

edited Oct 9, 2011 at 0:56

answered Oct 9, 2011 at 0:43

Ilmari Karonen

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6 Comments

Aurelio De Rosa Over a year ago

This solution slow the performance. RegEx are always slower than string comparison.

Ilmari Karonen Over a year ago

Regex compilation does carry an overhead, but so does foreach. I haven't done a benchmark, but I wouldn't be surprised if this wasn't faster than the foreach-based solutions.

Ilmari Karonen Over a year ago

@AurelioDeRosa: I did run a quick benchmark, and it seems that using preg_grep() is from twice (for the three-element input array given by the OP) to four times (for a 98000 word dictionary) faster than using foreach and stripos() as in your answer.

Aurelio De Rosa Over a year ago

You answered yourself. Test regex in a real contest. Use an array of thousand element where every value have a long lenght and then the test will says something correct. Anyway you can ask to everyone you want and everybody will tell you that the regex have to be used mildly.

Ilmari Karonen Over a year ago

@AurelioDeRosa: OK, since you insist: 1000 lines (of which 220 match), 302262 bytes total (avg. 302.262 bytes/line), repeated 10000 times: preg_grep() 15.940 seconds; stripos() 31.509 seconds. If you don't find these benchmarks convincing, why not try running your own?

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