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Find the last element of an array while using a foreach loop in PHP

I am writing a SQL query creator using some parameters. In Java, it's very easy to detect the last element of an array from inside the for loop by just checking the current array position with the array length.

for(int i=0; i< arr.length;i++){
     boolean isLastElem = i== (arr.length -1) ? true : false;        
}

In PHP they have non-integer indexes to access arrays. So you must iterate over an array using a foreach loop. This becomes problematic when you need to take some decision (in my case to append or/and parameter while building query).

I am sure there must be some standard way of doing this.

How do you solve this in PHP?

Are you trying to determine if you should concat an "AND" or "OR" between parts of a where clause?
just pointing out that you should store the total in a variable instead of calling a method for every iteration. for(int i=0, int t = arr.length; i
Take a look at this solution: stackoverflow.com/a/29474468/1478566
use end(arrray) use simmilar answers

h
hakre

It sounds like you want something like this:

$numItems = count($arr);
$i = 0;
foreach($arr as $key=>$value) {
  if(++$i === $numItems) {
    echo "last index!";
  }
}    

That being said, you don't -have- to iterate over an "array" using foreach in php.


$numItems = count($arr) trick is not needed and reduces readability - in PHP there is no performance penalty for accessing count($arr) each time. The reason is that items count is internally saved as special field in the array header and is not calculated on-the-fly. This trick comes from other languages (C, Java?,...).
That's interesting @johndodo that there's no performance penalty for accessing count($arr) each time. Do you have any links/sources to where this particular optimisation is documented? Thanks!
It's rather sad that in PHP the most correct solution to this problem looks rather inelegant :(
@tomsihap $i needs to be incremented inside the loop, in tandem with the array iteration. $i needs to represent the number of the item in the array, so that it can be used to determine when the last item has been reached. Without the ++ the loop would only ever compare "0" with the total number of items.
SINCE PHP 7.3 UNTIL NOW You could get the value of the last key of the array using array_key_last($array)
P
Paige Ruten

You could get the value of the last key of the array using end(array_keys($array)) and compare it to the current key:

$last_key = end(array_keys($array));
foreach ($array as $key => $value) {
    if ($key == $last_key) {
        // last element
    } else {
        // not last element
    }
}

+1 I agree - the other solutions rely on the array having numeric indexes.
In my own defense, my answer doesn't rely on the array having numeric keys :)
string comparison is slower then integers, and not always accurate when comparing strings to integers (you should at least have used ===). Im voting this down.
it's elegant, but causes STRICT NOTICE because "end" expects a reference value :(
Fix for STRICT NOTICE: $lastKey = array_search(end($array), $array);
P
PiTheNumber

Note: This doesn't work because calling next() advances the array pointer, so you're skipping every other element in the loop

why so complicated?

foreach($input as $key => $value) {
    $ret .= "$value";
    if (next($input)==true) $ret .= ",";
}

This will add a , behind every value except the last one!


Not if the next $input contains a boolean value of false, which is a major problem with next().
Unless I'm mistaken, this doesn't work because calling next() advances the array pointer, so you're skipping every other element in the loop.
Doesn't seem to work for me. The second last element doesn't get the comma but it should.
If the value equates to bool false it doesn't work. Also doesn't print the last comma between the second to last and last value.
A note for anyone wanting to use this in PHP7 - the array pointer doesn't move in foreach loops, and this will not work.
O
OIS

When toEnd reaches 0 it means it is at the last iteration of the loop.

$toEnd = count($arr);
foreach($arr as $key=>$value) {
  if (0 === --$toEnd) {
    echo "last index! $value";
  }
}

The last value is still available after the loop, so if you just want to use it for more stuff after the loop this is better:

foreach($arr as $key=>$value) {
  //something
}
echo "last index! $key => $value";

If you do not want to treat the last value as special inside loops. This should be faster if you have large arrays. (If you reuse the array after the loop inside the same scope you have to "copy" the array first).

//If you use this in a large global code without namespaces or functions then you can copy the array like this:
//$array = $originalArrayName; //uncomment to copy an array you may use after this loop

//end($array); $lastKey = key($array); //uncomment if you use the keys
$lastValue = array_pop($array);

//do something special with the last value here before you process all the others?
echo "Last is $lastValue", "\n";

foreach ($array as $key => $value) {
    //do something with all values before the last value
    echo "All except last value: $value", "\n";
}

//do something special with the last value here after you process all the others?
echo "Last is $lastValue", "\n";

And to answer your original question "in my case to append or/and parameter while building query"; this will loop over all the values, then join them together to a string with " and " between them but not before the first value or after the last value:

$params = [];
foreach ($array as $value) {
    $params[] = doSomething($value);
}
$parameters = implode(" and ", $params);

Of course it will perform the --$toEnd for every iteration, thats the point. If I moved it outside the loop, it would not work anymore.
The simplest method ever used. $lastValue = array_pop($array); Thank you.
h
hakre

There are already many answers, but it's worth to look into iterators as well, especially as it has been asked for a standard way:

$arr = range(1, 3);

$it = new CachingIterator(new ArrayIterator($arr));
foreach($it as $key => $value)
{
  if (!$it->hasNext()) echo 'Last:';
  echo $value, "\n";
}

You might find something that does work more flexible for other cases, too.


Great answer. I appreciate that you are using the features of the language that are intended for the task. i=0; and ++i; have always seemed hackish in a scripting language like PHP.
R
Raheel

One way could be to detect if the iterator has next. If there is no next attached to the iterator it means you are in the last loop.

foreach ($some_array as $element) {
    if(!next($some_array)) {
         // This is the last $element
    }
}

Doesn't work with PHP 7+ as "In PHP 7, foreach does not use the internal array pointer.".
T
TechDogLover OR kiaNasirzadeh

SINCE PHP 7.3 :

You could get the value of the last key of the array using array_key_last($array) and compare it to the current key:

$last_key = array_key_last($array);
foreach ($array as $key => $value) {
    if ($key == $last_key) {
        // last element
    } else {
        // not last element
    }
}

D
Darkcoder

to get first and last element from foreach array

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

    if ($value === end($array)) {
        echo 'LAST ITEM!';
    }
}

this seams to be very slow since you allways call 2 function to get compare value
R
Rok Kralj

So, if your array has unique array values, then determining last iteration is trivial:

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

As you see, this works if last element is appearing just once in array, otherwise you get a false alarm. In it is not, you have to compare the keys (which are unique for sure).

foreach($array as $key => $element) {
    end($array);
    if ($key === key($array))
        echo 'LAST ELEMENT!';
}

Also note the strict coparision operator, which is quite important in this case.


this is quite inefficient way.
Nope. It is not. end() performs O(1). It is also shorter than other solutions, and it reads out nicely -> If element equals end of the array write "Last".
This is more than twice as slow as my first and last examples for 100000 values.
n
nickf

You can still use that method with associative arrays:

$keys = array_keys($array);
for ($i = 0, $l = count($array); $i < $l; ++$i) {
    $key = $array[$i];
    $value = $array[$key];
    $isLastItem = ($i == ($l - 1));
    // do stuff
}

// or this way...

$i = 0;
$l = count($array);
foreach ($array as $key => $value) {
    $isLastItem = ($i == ($l - 1));
    // do stuff
    ++$i;
}

Please change $key = $array[$i]; to $key = $keys[$i]; in the first for loop.
M
Martin Heisterkamp

Assuming you have the array stored in a variable...

foreach($array as $key=>$value) 
{ 
    echo $value;
    if($key != count($array)-1) { echo ", "; }
}

This is very simple and useful. I would only count the array first outside the foreach loop so that the program won't have to count every time the foreach function evaluates each item.
This will not work on associative arrays. $key is not always a number.
you can also try with echo implode(",", $array)
V
Visavì

Don't add a comma after the last value:

The array:

$data = ['lorem', 'ipsum', 'dolor', 'sit', 'amet'];

The function:

$result = "";
foreach($data as $value) {
    $result .= (next($data)) ? "$value, " : $value;
}

The result:

print $result;

lorem, ipsum, dolor, sit, amet


A
Ankit Aggarwal

If you need to do something for every element except either the first or the last and only if there is more than one element in the array, I prefer the following solution.

I know there are many solutions above and posted months/one year before mine, but this is something I feel is fairly elegant in its own right. The check every loop is also a boolean check as opposed to a numeric "i=(count-1)" check, which may allow for less overhead.

The structure of the loop may feel awkward, but you can compare it to the ordering of thead (beginning), tfoot (end), tbody (current) in HTML table tags.

$first = true;
foreach($array as $key => $value) {
    if ($first) {
        $first = false;
        // Do what you want to do before the first element
        echo "List of key, value pairs:\n";
    } else {
        // Do what you want to do at the end of every element
        // except the last, assuming the list has more than one element
        echo "\n";
    }
    // Do what you want to do for the current element
    echo $key . ' => ' . $value;
}

For instance, in web development terms, if you want to add a border-bottom to every element except the last in an unordered list (ul), then you can instead add a border-top to every element except the first (the CSS :first-child, supported by IE7+ and Firefox/Webkit supports this logic, whereas :last-child is not supported by IE7).

You can feel free to reuse the $first variable for each and every nested loop as well and things will work just fine since every loop makes $first false during the first process of the first iteration (so breaks/exceptions won't cause issues).

$first = true;
foreach($array as $key => $subArray) {
    if ($first) {
        $string = "List of key => value array pairs:\n";
        $first = false;
    } else {
        echo "\n";
    }

    $string .= $key . '=>(';
    $first = true;
    foreach($subArray as $key => $value) {
        if ($first) {
            $first = false;
        } else {
            $string .= ', ';
        }
        $string .= $key . '=>' . $value;
    }
    $string .= ')';
}
echo $string;

Example output:

List of key => value array pairs:
key1=>(v1_key1=>v1_val1, v1_key2=>v1_val2)
key2=>(v2_key1=>v2_val1, v2_key2=>v2_val2, v2_key3=>v2_val3)
key3=>(v3_key1=>v3_val1)

Thanx, this is my favourite solution! It's very flexible and costs only a boolean. BTW, i think this will work for array containing at least one element too (not only more than one element).
D
Dulitha K

This should be the easy way to find the last element:

foreach ( $array as $key => $a ) {
    if ( end( array_keys( $array ) ) == $key ) {
        echo "Last element";
     } else {
        echo "Just another element";
     }
}  

Reference : Link


- broken link -
Y
Your Common Sense

I have a strong feeling that at the root of this "XY problem" the OP wanted just implode() function.


true. There are cases though where implode is just not as practical. Imagine for example trying to implode a long string of html with lots of dynamic variables in it. Sure, you could do a ob_start/ob_get_clean on it, or just build it as a $str ='...'. But, there are times when this could be considered just a tad overkill
A
Angelin Nadar

As your intention of finding the EOF array is just for the glue. Get introduced to the below tactic. You need not require the EOF:

$given_array = array('column1'=>'value1',
                     'column2'=>'value2',
                     'column3'=>'value3');

$glue = '';
foreach($given_array as $column_name=>$value){
    $where .= " $glue $column_name = $value"; //appending the glue
    $glue   = 'AND';
}
echo $where;

o/p:

column1 = value1 AND column2 = value2 AND column3 = value3

Ç
Çağ
A
Ashique CM

It sounds like you want something like this:

$array = array(
    'First',
    'Second',
    'Third',
    'Last'
);

foreach($array as $key => $value)
{
    if(end($array) === $value)
    {
       echo "last index!" . $value;
    }
}

Using the value usually isn't a good idea because it won't work properly if the array has two identical values.
h
helloandre

you can do a count().

for ($i=0;$i<count(arr);$i++){
    $i == count(arr)-1 ? true : false;
}

or if you're looking for ONLY the last element, you can use end().

end(arr);

returns only the last element.

and, as it turns out, you CAN index php arrays by integers. It's perfectly happy with

arr[1];

The drawback in end(arr) is it sets the array's internal pointer to the last element..
No, you SHOULDN'T use integers to access the arrays unless you know that the keys are numeric and sequential. Consider: $a = array(0=>'A', 2=>'B', 'aaa'=>'C'). What do you get if you access $a[count($a)-1]?
K
KOGI

You could also do something like this:

end( $elements );
$endKey = key($elements);
foreach ($elements as $key => $value)
{
     if ($key == $endKey) // -- this is the last item
     {
          // do something
     }

     // more code
}

end returns the value not the array, so the way you made it doesnt work. string comparison is also slower then integer.
You are right. it should be end($elements); $endKey = key($elements);
A
Alastair Brayne

I kinda like the following as I feel it is fairly neat. Let's assume we're creating a string with separators between all the elements: e.g. a,b,c

$first = true;
foreach ( $items as $item ) {
    $str = ($first)?$first=false:", ".$item;
}

make it more simple without declaring $first; use foreach ( $items as $key=>$item ) then $str = ($key==0)?
I
ITWitch

Here's my solution: Simply get the count of your array, minus 1 (since they start in 0).

$lastkey = count($array) - 1;
foreach($array as $k=>$a){
    if($k==$lastkey){
        /*do something*/
    }
}

A
Ayman Elshehawy
foreach ($array as $key => $value) {

  $class = ( $key !== count( $array ) -1 ) ? " class='not-last'" : " class='last'";

  echo "<div{$class}>";
  echo "$value['the_title']";
  echo "</div>";

}

Reference


J
Justin Vincent

If it is a single dimensional array you can do this to keep it short and sweet:

foreach($items as $idx => $item) {
    if (!isset($items[$idx+1])) {
        print "I am last";
    }
}

F
FsCode
$array  = array("dog", "rabbit", "horse", "rat", "cat");
foreach($array as $index => $animal) {
    if ($index === array_key_first($array))
        echo $animal; // output: dog

    if ($index === array_key_last($array))
        echo $animal; // output: cat
}

K
Kevin

Here's another way you could do it:

$arr = range(1, 10);

$end = end($arr);
reset($arr);

while( list($k, $v) = each($arr) )
{
    if( $n == $end )
    {
        echo 'last!';
    }
    else
    {
        echo sprintf('%s ', $v);
    }
}

This answer is missing its educational explanation. echo sprintf() is an "antipattern". There is absolutely no reason that anyone should ever write echo sprintf() in any code for any reason -- it should be printf() every time.
J
James

If I understand you, then all you need is to reverse the array and get the last element by a pop command:

   $rev_array = array_reverse($array);

   echo array_pop($rev_array);

M
Mark

You could also try this to make your query... shown here with INSERT

<?php
 $week=array('one'=>'monday','two'=>'tuesday','three'=>'wednesday','four'=>'thursday','five'=>'friday','six'=>'saturday','seven'=>'sunday');
 $keys = array_keys($week);
 $string = "INSERT INTO my_table ('";
 $string .= implode("','", $keys);
 $string .= "') VALUES ('";
 $string .= implode("','", $week);
 $string .= "');";
 echo $string;
?>

M
Morg.

For SQL query generating scripts, or anything that does a different action for the first or last elements, it is much faster (almost twice as fast) to avoid using unneccessary variable checks.

The current accepted solution uses a loop and a check within the loop that will be made every_single_iteration, the correct (fast) way to do this is the following :

$numItems = count($arr);
$i=0;
$firstitem=$arr[0];
$i++;
while($i<$numItems-1){
    $some_item=$arr[$i];
    $i++;
}
$last_item=$arr[$i];
$i++;

A little homemade benchmark showed the following:

test1: 100000 runs of model morg

time: 1869.3430423737 milliseconds

test2: 100000 runs of model if last

time: 3235.6359958649 milliseconds


L
Leven

Another way to go is to remember the previous loop cycle result and use that as the end result:

    $result = $where = "";
    foreach ($conditions as $col => $val) {
        $result = $where .= $this->getAdapter()->quoteInto($col.' = ?', $val);
        $where .=  " AND ";
    }
    return $this->delete($result);