31

Wondering what would be a good method to get the first iteration on a foreach loop. I want to do something different on the first iteration.

Is a conditional our best option on these cases?

MEM
  • 30,529
  • 42
  • 121
  • 191

11 Answers11

82

Yes, if you are not able to go through the object in a different way (a normal for loop), just use a conditional in this case:

$first = true;
foreach ( $obj as $value )
{
    if ( $first )
    {
        // do something
        $first = false;
    }
    else
    {
        // do something
    }

    // do something
}
poke
  • 369,085
  • 72
  • 557
  • 602
43

Even morer eleganterer:

foreach($array as $index => $value) {
 if ($index == 0) {
      echo $array[$index];
 }
}

That example only works if you use PHP's built-in array append features/function or manually specify keys in proper numerical order.

Here's an approach that is not like the others listed here that should work via the natural order of any PHP array.

$first = array_shift($array);
//do stuff with $first

foreach($array as $elem) {
 //do stuff with rest of array elements
}

array_unshift($array, $first);     //return first element to top
Klinky
  • 2,084
  • 15
  • 12
  • @NathanBell Technically all arrays are associative in PHP. This example only works if you use PHP's built-in array append features/function or manually specify keys in proper numerical order. – Klinky Aug 17 '12 at 02:35
10

You can simply add a counter to the start, like so:

$i = 0;

foreach($arr as $a){
 if($i == 0) {
 //do ze business
 }
 //the rest
 $i++;
}
Russell Dias
  • 70,980
  • 5
  • 54
  • 71
6

I saw this solution on a blog post in my search result set that brought up this post and I thought it was rather elegant. Though perhaps a bit heavy on processing.

foreach ($array as $element) 
{
    if ($element === reset($array))
        echo 'FIRST ELEMENT!';

    if ($element === end($array))
        echo 'LAST ELEMENT!';
}

Do note there is also a warning on the post that this will only work if the array values are unique. If your last element is "world" and some random element in the middle is also "world" last element will execute twice.

danielson317
  • 3,121
  • 3
  • 28
  • 43
5

hm

<?php
$i = 0;
foreach($ar as $sth) {
    if($i++ == 0) {
        // do something
    }
    // do something else
}

more elegant.

janoliver
  • 7,744
  • 14
  • 60
  • 103
  • Will this actually work? Will $i be really incremented after evaluation of the statement? – yan.kun Oct 18 '10 at 09:21
  • 3
    @yan Well, either the *post-increment operator* works [as described](http://php.net/manual/en/language.operators.increment.php), or PHP is terribly broken... – deceze Oct 18 '10 at 09:23
  • yes. $i++ is evaluated after the expression, ++$i would be evaluated first. – janoliver Oct 18 '10 at 09:23
2
first = true
foreach(...)
    if first
        do stuff
        first = false
dutt
  • 7,909
  • 11
  • 52
  • 85
2

This is also works

foreach($array as $element) {
    if ($element === reset($array))
        echo 'FIRST ELEMENT!';

    if ($element === end($array))
        echo 'LAST ELEMENT!';
}
omukiguy
  • 1,401
  • 3
  • 17
  • 36
2
foreach($array as $element) {
    if ($element === reset($array))
        echo 'FIRST ELEMENT!';

    if ($element === end($array))
        echo 'LAST ELEMENT!';
}
  • While this may answer the question it's better to add some description on how this answer may help to solve the issue. Please read [How do I write a good answer](https://stackoverflow.com/help/how-to-answer) to know more. – Roshana Pitigala Jul 02 '18 at 18:52
1

Here's an example that does not use foreach loop

 <?php
    // A sample indexed array
    $cities = array("London", "Paris", "New York");
    echo $cities[0]; // Outputs: London
     
    // A sample associative array
    $fruits = array("a" => "Apple", "b" => "Ball", "c" => "Cat");
    echo array_values($fruits)["0"]; // Outputs: Apple
  ?>
mark
  • 11
  • 3
0

What about using key() native php function? which should work fine with all kind of arrays (indexed, associative ) as it will always return the first key no matter if its inside or outside the loop.

$array = array(
    'One'   => 'value',
    'Two'   => 'value-2',
    'Three' => 'value-3',
);

foreach ( $array as $index => $key ) {
    if ( key( $array ) ) {
        /**Do something with the first key*/
    } else {
        /**Do something else*/
    }
}

if it indexed array, you have many options you can go through, for me using counter is always fine and get the correct result all the time.

    $array = array(
        'One',
        'Two',
        'Three',
    );

    $i     = 0;
    foreach ( $array as $index => $key ) {
        if ( $array[ $i ] ) {
            /**Do something with the first key*/
        } else {
            /**Do something else*/

            $i++;
        }
    }

Both should work fine with $key => $value loop and it will only return the first key.

Also I would like to add something, You can always archive your target in scripting with hundreds of different way, Its all about the way you want to use in this situation.

Tariq Ahmed
  • 305
  • 3
  • 14
0

Your Query

$result = mysqli_query($conn, $sql) or die("Query failed!");
}

You'll get the first index row from your database

print_r(mysqli_fetch_assoc($result));