PHP - Grab the first element using a foreach

Wondering what would be a good method to get the first iteration on a foreach loop. I want to do something different 开发者_JAVA百科on the first iteration.

Is a conditional our best option on these cases?

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
}

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

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++;
}

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.

hm

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

more elegant.

first = true
foreach(...)
    if first
        do stuff
        first = false

This is also works

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

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

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

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

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
  ?>

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.