get first and last element in array

Question

hey there i have this array:

array(1) {
  ["dump"]=>
  string(38) "["24.0",24.1,24.2,24.3,24.4,24.5,24.6]"
}

my question:

how to get the first and the last element out from this array, so i will have:

$firstEle = "24.0";

and

$lastEle = "24.6";

anybody knows how to get those elements from the array?

i already tried this:

$arr = json_decode($_POST["dump"], true); 

$col0 = $arr[0];
$col1 = $arr[1];
$col2 = $arr[2];
$col3 = $arr[3];
$col4 = $arr[4];
$col5 = $arr[5];
$col6 = $arr[6];

i could chose $col0 and $col6, but the array could be much longer, so need a way to filter the first("24.0") and the last("24.6") element. greetings

Solution 1

reset() and end() does exactly this.

From the manual:

reset(): Returns the value of the first array element, or FALSE if the array is empty.

end(): Returns the value of the last element or FALSE for empty array.

Example:

<?php
    $array = array(24.0,24.1,24.2,24.3,24.4,24.5,24.6);
    
    $first = reset($array);
    $last = end($array);
    
    var_dump($first, $last);
?>

Which outputs:

float(24)
float(24.6)

DEMO

---

NOTE: This will reset your array pointer meaning if you use current() to get the current element or you've seeked into the middle of the array, reset() and end() will reset the array pointer (to the beginning and to the end):

<?php

$array = array(30.0, 24.0, 24.1, 24.2, 24.3, 24.4, 24.5, 24.6, 12.0);
    
// reset — Set the internal pointer of an array to its first element
$first = reset($array);

var_dump($first); // float(30)
var_dump(current($array)); // float(30)

// end — Set the internal pointer of an array to its last element
$last = end($array);
    
var_dump($last); // float(12)
var_dump(current($array)); // float(12) - this is no longer 30 - now it's 12

Solution 2

You can accessing array elements always with square bracket syntax. So to get the first use 0, as arrays are zero-based indexed and count($arr) - 1 to get the last item.

$firstEle = $arr[0];
$lastEle = $arr[count($arr) - 1];

Solution 3

As of PHP 7.3, array_key_first and array_key_last is available

$first = $array[array_key_first($array)];    
$last = $array[array_key_last($array)];

Solution 4

You can use reset() to get the first:

$firstEle = reset($arr);

reset() rewinds array's internal pointer to the first element and returns the value of the first array element.

And end() to get the last:

$lastEle = end($arr);

end() advances array's internal pointer to the last element, and returns its value.

Solution 5

For first element: current($arrayname);

For last element: end($arrayname);

current(): The current() function returns the value of the current element in an array. Every array has an internal pointer to its "current" element, which is initialized to the first element inserted into the array.

end(): The end() function moves the internal pointer to, and outputs, the last element in the array. Related methods: current() - returns the value of the current element in an array

$array = array(24.0,24.1,24.2,24.3,24.4,24.5,24.6);

$first = current($array);
$last = end($array);

echo 'First Element: '.$first.' :: Last Element:'.$last;

Output result:

First Element: 24 :: Last Element:24.6

View more solutions

Comments

[gen_Eric]

Have a look at reset() and end(). P.S. 0 will always be the 1st element, and for the last you can do $arr[count($arr)-1].

[user2999787]

yeah but take a look at my array, when i use your code, i get: "Warning: reset() expects parameter 1 to be array, null given" and the same for end()

[AliN11]

Be aware of using this method. $array = array(1, 2, 3); echo current($array) . " "; echo end($array) . " "; echo current($array) . " "; returns 1 3 3