How to concatenate PHP variable name?

Question

I have a PHP for loop:

for ($counter=0,$counter<=67,$counter++){

echo $counter;
$check="some value";

}

What I am trying to achieve is use the for loop variable and append it to the name of another variable.

Bascially, I want the PHP output to be as follows for each row

1
$check1="some value"

2
$check2="some value"

3
$check3="some value"

4
$check4="some value"

etc etc

I have tried $check.$counter="some value" but this fails.

How can I achieve this? Am I missing something obvious?

Would the use of an `array` be preferable to this method? `$myVar = array(); for($i = 0; $i <= 67; $i++) { $myVar[] = "Some Value"; }` — Matt, Jul 31 '12 at 12:40

score 75 · Accepted Answer · 2017-09-26T12:46:04.240

75

The proper syntax for variable variables is:

${"check" . $counter} = "some value";

However, I highly discourage this. What you're trying to accomplish can most likely be solved more elegantly by using arrays. Example usage:

// Setting values
$check = array();
for ($counter = 0; $counter <= 67; $counter++){
    echo $counter;
    $check[] = "some value";
}

// Iterating through the values
foreach($check as $value) {
    echo $value;
}

edited Sep 26 '17 at 12:46

answered Jul 31 '12 at 12:39

Thanks Tim, is there a situaton when this is acceptable or is it functionality no longer used? – Smudger Jul 31 '12 at 12:50
1

@Smudger: Off the top of my head, I can't think of a solid case where one would use variable variables. Looking at the [comments on the documentation page](http://php.net/manual/en/language.variables.variable.php#usernotes) might give you some ideas on where they could be useful. Just keep in mind that what you read there may not be considered best practice. – Jul 31 '12 at 12:55
Concatenation is never the "cleaner" solution, but there may be cases where you have old, highly developed code that was never intended to correlate A+B where it is simply much easier to do this than rewriting hundreds of lines of code just to replace old variable types with arrays – Nosajimiki Jul 13 '17 at 21:46
The one case I can think of where I use them is with HTML forms where I have recursively built inputs. When you Post it, it will post as a bunch of variables and not as an array; so, recursively calling them may be easier with $_POST[${"myInputName".$i}] – Nosajimiki Jul 13 '17 at 22:00

score 6 · Answer 2 · answered Jul 31 '12 at 12:43

6

You should use ${'varname'} syntax:

for ($counter=0,$counter<=67,$counter++){
    echo $counter;
    ${'check' . $counter} ="some value";
}

this will work, but why not just use an array?

$check[$counter] = "some value";

answered Jul 31 '12 at 12:43

Adunahay

1,551
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score 6 · Answer 3 · answered Jul 09 '13 at 18:39

6

This is usable in some cases. For example if your app has something like 2 language entries in DB.

echo $this->{'article_title_'.$language};

That's much more usable than for example this;

if($language == 'mylanguage1')
    echo $this->article_title_mylanguage1;
else
    echo $this->article_title_mylanguage2;

Obviously this is what you should not have to do in your multilingual app, but i have seen cases like this.

answered Jul 09 '13 at 18:39

arma

4,084
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Yeah, it is my case: I got 3 columns entries in DB. So i need to loop like that from a checkboxes group – Pathros Sep 22 '18 at 12:46

score 0 · Answer 4 · answered Jul 31 '12 at 12:42

0

An array would accomplish this.

$check = array();

for($counter = 0; $counter <= 67; $counter++) {
    $check[] = "some value";
    var_dump($check[$counter]);
}

answered Jul 31 '12 at 12:42

Matt

6,993
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50

How to concatenate PHP variable name?

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