PHP Associative array - php

Question

I have an array as
$arrTest = array('val1','val2','val3','val4');
$arrTest['lastKey'] = 'Last Key';
foreach($arrTest as $key => $val) {
if($key == 'lastKey') {
echo "last found";
}
}
The above code is not working. I have added associative element in the array. Could it be the reason?

Answer 1

Change == to === in:
if($key == 'lastKey')
Your existing code echos last found twice, once for key 0 and once for key lastKey.
Comparing integer 0 and string 'lastKey' using == returns true !!
From the PHP manual:
String conversion to numbers
When a string is evaluated in a
numeric context, the resulting value
and type are determined as follows.
The string will be evaluated as a
float if it contains any of the
characters '.', 'e', or 'E'.
Otherwise, it will be evaluated as an
integer.
The value is given by the initial
portion of the string. If the string
starts with valid numeric data, this
will be the value used. Otherwise, the
value will be 0 (zero). Valid numeric
data is an optional sign, followed by
one or more digits (optionally
containing a decimal point), followed
by an optional exponent. The exponent
is an 'e' or 'E' followed by one or
more digits.

Answer 2

Use === to compare. Because when key 0 will be compared with string lastKey, string will be converted to integer and false result will be returned.
http://codepad.org/5QYIeL4f
$arrTest = array('val1','val2','val3','val4');
$arrTest['lastKey'] = 'Last Key';
foreach($arrTest as $key => $val) {
if($key === 'lastKey') {
echo "last found";
}
}
Read more about differences: http://php.net/manual/en/language.operators.comparison.php

Answer 3

You need to change your equality condition to check the type as well.
if($key === 'lastKey')
This is because PHP evaluates ' ' == 0 as true.

Answer 4

When I ran your code, 'last found' was outputted twice. 'lastKey' is evaluated to 0 in PHP, so if($key == 'lastKey') actually matches twices: once for 0 and once for your special element.

Answer 5

use the end() function to get the last key of an array and compare it in your if statement.
$arrTest = array('val1','val2','val3','val4');
$lastKey = end($arrTest);
foreach($arrTest as $key => $val) {
if($val == $lastKey) {
echo "last found";
}
}

Answer 6

Your code is working fine :
see it here : http://codepad.org/hfOFHMnc
However use "===" instead of "==" as you might encounter a bug when
comparing the string with 0 , and it will echo twice.
<?php
$arrTest = array('val1','val2','val3','val4');
$arrTest['lastKey'] = 'Last Key';
print_r($arrTest);
foreach($arrTest as $key => $val) {
if($key == 'lastKey') { // use === here
echo "key = $key :: last found \n";
}
}

Answer 7

If you want to test if an array key exists, simply use array_key_exists:
array_key_exists('lastKey', $arrTest)
You could also use isset but note that it returns false if the value associated to the key is null.