How to skip the 1st key in an array loop?
PhpArraysPhp Problem Overview
I have the following code:
if ($_POST['submit'] == "Next") {
foreach($_POST['info'] as $key => $value) {
echo $value;
}
}
How do I get the foreach function to start from the 2nd key in the array?
Php Solutions
Solution 1 - Php
For reasonably small arrays, use array_slice to create a second one:
foreach(array_slice($_POST['info'],1) as $key=>$value)
{
echo $value;
}
Solution 2 - Php
foreach(array_slice($_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 $value;
}
Solution 3 - Php
Couldn't you just unset the array...
So if I had an array where I didn't want the first instance, I could just:
unset($array[0]);
and that would remove the instance from the array.
Solution 4 - Php
If you were working with a normal array, I'd say to use something like
foreach (array_slice($ome_array, 1) as $k => $v {...
but, since you're looking at a user request, you don't have any real guarantees on the order in which the arguments might be returned - some browser/proxy might change its behavior or you might simply decide to modify your form in the future. Either way, it's in your best interest to ignore the ordering of the array and treat POST values as an unordered hash map, leaving you with two options :
- copy the array and
unset
the key you want to ignore - loop through the whole array and
continue
when seeing the key you wish to ignore
Solution 5 - Php
in loop:
if ($key == 0) //or whatever
continue;
Solution 6 - Php
Alternative way is to use array pointers:
reset($_POST['info']); //set pointer to zero
while ($value=next($_POST['info']) //ponter+1, return value
{
echo key($_POST['info']).":".$value."\n";
}
Solution 7 - Php
If you're willing to throw the first element away, you can use array_shift()
. However, this is slow on a huge array. A faster operation would be
reset($a);
unset(key($a));
Solution 8 - Php
On a array filled with 1000 elements the difference is quite minimal.
Test:
<?php
function slice($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)
Solution 9 - Php
Working Code From My Website For Skipping The First Result and Then Continue.
<?php
$counter = 0;
foreach ($categoriest as $category) { if ($counter++ == 0) continue; ?>
It is working on opencart also in tpl file do like this in case you need.
Solution 10 - Php
foreach($_POST['info'] as $key=>$value) {
if ($key == 0) { //or what ever the first key you're using is
continue;
} else {
echo $value;
}
}
foreach($_POST['info'] as $key=>$value) {
if ($key == 0) { //or what ever the first key you're using is
continue;
} else {
echo $value;
}
}
Solution 11 - Php
if you structure your form differently
<input type='text' name='quiz[first]' value=""/>
<input type='text' name='quiz[second]' value=""/>
...then in your PHP
if( isset($_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
Solution 12 - Php
How about something like this? Read off the first key and value using key()
and current()
, then (EDIT: Don't use array_shift()
to dequeue the front element from the arrayarray_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( "<p>OK, first values are $firstKey, $firstVal</p>" ) ;
####<del>array_shift( $arr ) ; #'dequeue' front element</del> # BAD! renumbers!
unset( $arr[ $firstKey ] ) ; # BETTER!
echo( "<p>Now for the rest of them</p>" ) ;
foreach( $arr as $key=>$val )
{
echo( "<p>$key => $val</p>" ) ;
}
?>