How to skip the 1st key in an array loop?

Question

I have the following code:

if ($_POST['submit'] == "Next") {
    foreach($_POST['info'] as $key => $value) {
     echo $value;
    }
}

How do I get the foreach function to start from the 2nd key in the array? Thanx.

Answer 1

in loop:

if ($key == 0) //or whatever
   continue;

Answer 2

foreach(array_slice($_POST['info'], 1) as $key=>$value) {
    echo $value;
}

Alternatively if you don't want to copy the array you could just do:

$isFirst = true;
foreach($_POST['info'] as $key=>$value) {
    if ($isFirst) {
        $isFirst = false;
        continue;
    }   
    echo $value;
}

Answer 3

For reasonably small arrays, use array_slice to create a second one:

foreach(array_slice($_POST['info'],1) as $key=>$value)
{
    echo $value;
}

Answer 4

foreach($_POST['info'] as $key=>$value) {
    if ($key == 0) { //or what ever the first key you're using is
        continue;
    }  else { 
        echo $value;
    }
}

Answer 5

If you were working with a normal array, I'd say to use something like

foreach (array_slice($ome_array, 1) as $k => $v {...

but, since you're looking at a user request, you don't have any real guarantees on the order in which the arguments might be returned - some browser/proxy might change its behavior or you might simply decide to modify your form in the future. Either way, it's in your best interest to ignore the ordering of the array and treat POST values as an unordered hash map, leaving you with two options :

• copy the array and unset the key you want to ignore
• loop through the whole array and continue when seeing the key you wish to ignore

Answer 6

if you structure your form differently

  <input type='text' name='quiz[first]' value=""/>
  <input type='text' name='quiz[second]' value=""/>

...then in your PHP

if( isset($_POST['quiz']) AND 
    is_array($_POST['quiz'])) {

    //...and we'll skip $_POST['quiz']['first'] 
    foreach($_POST['quiz'] as $key => $val){
      if($key == "first") continue;
      print $val; 
    }
}

...you can now just loop over that particular structure and access rest normally

Answer 7

On a array filled with 1000 elements the difference is quite minimal.

Test:

<?php
function slice($a)
{
    foreach(array_slice($a, 1) as $key)
    {

    }

    return true;
}

function skip($a)
{
    $first = false;

    foreach($a as $key)
    {
     if($first)
     {
      $first = false;
      continue;
     }
    }

    return true;
}

$array = array_fill(0, 1000, 'test');

$t1 = time() + microtime(true);

for ($i = 0; $i < 1000; $i++)
{
    slice($array);
}

var_dump((time() + microtime(true)) - $t1);

echo '<hr />';

$t2 = time() + microtime(true);

for ($i = 0; $i < 1000; $i++)
{
    skip($array);
}

var_dump((time() + microtime(true)) - $t2);
?>

Output:

float(0.23605012893677)

float(0.24102783203125)

Answer 8

If you're willing to throw the first element away, you can use array_shift(). However, this is slow on a huge array. A faster operation would be

reset($a);
unset(key($a));

Answer 9

How about something like this? Read off the first key and value using key() and current(), then array_shift() to dequeue the front element from the array (EDIT: Don't use array_shift(), it renumbers any numerical indices in the array, which you don't always want!).

    <?php

    $arr = array(

      'one' => "ONE!!",
      'two' => "TWO!!",
      'three' => "TREE",
      4 => "Fourth element",
      99 => "We skipped a few here.."

    ) ;

    $firstKey = key( $arr ) ;
    $firstVal = current( $arr ) ;

    echo( "
OK, first values are $firstKey, $firstVal
" ) ;
    ####array_shift( $arr ) ; #'dequeue' front element # BAD! renumbers!
    unset( $arr[ $firstKey ] ) ;  # BETTER!

    echo( "
Now for the rest of them
" ) ;
    foreach( $arr as $key=>$val )
    {
      echo( "
$key => $val
" ) ;
    }

    ?>