Get the last element of an array, without changing its internal pointer

Question

How can I get the last element of an array without changing its internal pointer?

What i'm doing is:

while(list($key, $value) = each($array)) {  
    //do stuff  
    if($condition) {  
        //Here I want to check if this is the last element of the array            
        prev($array);  
    }  
}

so end($array) would mess things up.

Hint: `array_keys`. Also, click the big orange question mark to get formatting help and instructions. — Charles, Dec 15 '12 at 09:44
@PankitKapadia `end()` changes the arrays internal pointer, and it's mentioned in the question that it isn't of any help. — undefined, Dec 15 '12 at 09:54
Does that array may contain associative keys (keys with not just integers but also strings)? — brunoais, Dec 15 '12 at 10:02
No. If you noticed - the array pointer is changed within the loop, so a counter is not a suitable solution. — undefined, Dec 15 '12 at 10:04
@brunoais No. But the indexes are neither sorted, nor sequential. — undefined, Dec 15 '12 at 10:13
"so end($array) would mess things up." Not if you use it like I did. Also consider and check to see if my code is better than the other ones. — brunoais, Dec 15 '12 at 10:24

score 2 · Answer 1 · answered Dec 15 '12 at 10:00

2

Try this:

<?php
$array=array(1,2,3,4,5);
$totalelements = count($array);
$count=1;

while(list($key, $value) = each($array)) {  
    //do stuff  
    if($count == $totalelements){ //check here if it is last element
        echo $value;
    }
    $count++;
}
?>

answered Dec 15 '12 at 10:00

Pankit Kapadia

1,579
13
25

Can be done like `for($count=1;list($key, $value) = each($array));$count++)` – undefined Dec 15 '12 at 10:05

score 2 · Accepted Answer · answered Dec 15 '12 at 10:15

2

It's simple, you could use:

$lastElementKey = end(array_keys($array));
while(list($key, $value) = each($array)) {  
    //do stuff  
    if($key == $lastElementKey) {  
        //Here I want to check if this is the last element of the array            
        prev($array);  
    }  
}

answered Dec 15 '12 at 10:15

DiverseAndRemote.com

19,314
10
61
70

I ended up using the solution in the answer of [this question](http://stackoverflow.com/questions/7490818/get-the-last-element-of-an-array-without-changing-the-array-in-php) – undefined Dec 15 '12 at 10:18
2

Not sure how that answer applies but ok – DiverseAndRemote.com Dec 15 '12 at 10:18
The answer provided in that other question wont work for you if your array contains the same value more than once. The correct way is to check the keys and not the values. – DiverseAndRemote.com Dec 15 '12 at 10:24
My solution uses no if's so I suppose that it is faster. – brunoais Dec 15 '12 at 10:25
It does the job (the array has distinct values). – undefined Dec 15 '12 at 10:25
The first line has moved the internal pointer for the array, has it not? – Scott Flack Oct 30 '17 at 06:07

score 1 · Answer 3 · answered Dec 15 '12 at 10:22

1

Why not just using something like:

$lastElement= end($array);
reset($array);
while(list($key, $value) = each($array)) {  
    //do stuff   
}

// Do the extra stuff for the last element

answered Dec 15 '12 at 10:22

brunoais

6,258
8
39
59

not a good solution if the first and last elements are the same. The correct solution is to use the array keys. – DiverseAndRemote.com Dec 15 '12 at 10:25
I wanted to check if `$value` is the last element. – undefined Dec 15 '12 at 10:26
@xyu ? Why doesn't it work? From what I understood, you wanted to check it to do something else with it, right? You want to do the same thing for all elements except the last one where you want to do some extra stuff – brunoais Dec 15 '12 at 10:26
It does. I never said it doesn't. – undefined Dec 15 '12 at 10:31
Oh... ok. I thought that you were writing like that because it wasn't a solution for the problem you stated. – brunoais Dec 15 '12 at 10:34

score 0 · Answer 4 · answered Dec 15 '12 at 10:11

Something like this:

$array = array_reverse($array, true);
$l = each($array);
$lastKey = $l['key'];
$array = array_reverse($array, true);

while(list($key, $value) = each($array)) {  
    //do stuff  
    if($key == $lastKey) {  
        echo $key . ' ' . $value . PHP_EOL;
    }  
}

The problem here is that if the array is big one then it'll take some time to reverse it.

Get the last element of an array, without changing its internal pointer

4 Answers4