how to get key by value in array

Question

I have some problem to fetching key of matching value in array. Here is my array,

Array
(
    [0] => Array
        (
            [0] => 1001;vbaker;[email protected];Vern;Baker;
        )

    [1] => Array
        (
            [0] => 1002;Tesdsd;[email protected];Test;vbaker;
        )

    [2] => Array
        (
            [0] => 1003;demosa;[email protected];Baker;Tesdsd;
        )

)

So here for example, I want get key of 1002(value).. How do I get that ..? My need is ,I have only the id(say 1002) so I have to get the other values like Tesdsd;[email protected];Test;vbaker;

Loop through the array and use explode() to separate on the semicolon? — Mattt
– Mattt, Commented Apr 23, 2014 at 16:57
By "key", do you mean the index of the outer array? So given 1002, you want the result to be 1? — Patrick Q
– Patrick Q, Commented Apr 23, 2014 at 16:58
Each element in your array is an array of length 1, each solo-child element containing a string. Are you suggesting that you explode that string into an array (delimiter ;) such that the expected result searching for "1002" would be [1][0][0]? — Popnoodles
– Popnoodles, Commented Apr 23, 2014 at 17:13

Amal · Accepted Answer · 2014-04-23 17:04:50Z

1

Loop through the array, split on ;, store the first and last parts into variables ($first and $last), check if $first is the same as your search string, and if so return $last:

$search = 1002;

foreach ($array as $key => $sub) {
    list($first, $last) = explode(';', $sub[0], 2);
    if ($first == $search) {
        echo $last;
    }
}

Output:

Tesdsd;[email protected];Test;vbaker;

Demo

edited Apr 23, 2014 at 17:04

answered Apr 23, 2014 at 16:59

Amal

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5 Comments

Elavarasan Over a year ago

Thanks for your help.But I need to get the key..for fetching other values..please have a look at my updated question..

Amal Over a year ago

@Elavarasan: I'm confused after seeing your update. Could you edit your question to include the expected result so that I can understand what you're trying to do?

Elavarasan Over a year ago

The array is a csv file. I just convert it to array. It contains users details, like id, name, email etc..For my purpose I want get all details of that user by id. So I want get details of user_id 1002. How do I achieve that ..?

Amal Over a year ago

@Elavarasan: Personally, I'd use something like while (($data = fgetcsv($handle, 1000, ";")) !== FALSE) { ... } and store it in an array and then search the array afterwards. But does this answer your question?

Elavarasan Over a year ago

Thanks Amal..Finally I got fixed with your answer, but additionally I want get the key for the matching value(1002).. like. $array[0][1][0];

AbraCadaver · Accepted Answer · 2014-04-23 17:04:29Z

1

To get the value:

$search = 1002;
$result = array_values(preg_grep("/$search/", call_user_func_array('array_merge', $array)))[0];

Which gives:

1002;Tesdsd;[email protected];Test;vbaker;

Then you can explode() on ; and get the parts you want.

To get the key/index (which is 1) try:

$search = 1002;
$key = key(preg_grep("/$search/", call_user_func_array('array_merge', $array)));

answered Apr 23, 2014 at 17:04

AbraCadaver

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Comments

Quasdunk · Accepted Answer · 2014-04-23 17:24:13Z

1

Because I love PHP's array functions so much, here are my 2 cents:

$search = '1003';

$matches = array_filter($array, function($v) use ($search) {

    return strpos($v[0], $search) !== false;

});

echo 'The keys are: ' . implode(', ', array_keys($matches));

//EDIT:

If you don't actually need the keys (as you said in your original question) but also want to work with the values, this may be a better approach:

$search = '1003';

array_walk($array, function($v, $k) use ($search) {

    if ( strpos($v[0], $search) !== false )
    {
        // do whatever you want with the data
        echo 'Found ' . ltrim($v[0], $search.';') . ' at key ' . $k;
    }

});

The other answers will also do the trick, but as I said, I'm a huge fan of array functions, because I find them more elegant than loops.

edited Apr 23, 2014 at 17:24

answered Apr 23, 2014 at 17:09

Quasdunk

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3 Comments

Quasdunk Over a year ago

@AmalMurali What the... The updated question is completely different from the original one.

Amal Over a year ago

Yes. The updated question reads "My need is ,I have only the id(say 1002) so I have to get the other values like Tesdsd;[email protected];Test;vbaker" — your code will output 2 (which I assume is not what the OP wants).

Quasdunk Over a year ago

@AmalMurali Thanks for the clarification, I've updated my answer accordingly.

martskins · Accepted Answer · 2014-04-23 16:59:56Z

0

This should get you on the right tracks...

$yourKey = null;
foreach ($arr as $key => $value) {
    if($value == $someSearchQuery){
        $yourKey = $key;
    }
}

answered Apr 23, 2014 at 16:59

martskins

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1 Comment

martskins Over a year ago

Yeah, you're right.. this should get him into the right tracks though.

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