I have this php code:
$A = ['dog', 'cat', 'monkey'];
$B = ['cat', 'rat', 'dog', 'monkey'];
foreach ($A as $animal) {
if (!in_array($animal, $B)) {
echo "$animal doesn't exist<br>";
}
}
But the if statement never executes. What I'm I doing wrong? What is the proper way to check if a value doesn't exist in array?
With use of php in_array() and ternary operator.
$A=['dog', 'cat', 'monkey'];
$B=['cat', 'rat', 'dog', 'monkey'];
foreach($A as $animal) {
$result[] = in_array($animal, $B) ? "$animal exist": "$animal does not exist";
}
var_dump($result);
<?php
$A=['dog', 'cat', 'monkey'];
$B=['cat', 'rat', 'dog', 'monkey'];
foreach($B as $animal) {
if(!in_array($animal, $A)) {
echo "$animal doesn't exist<br>";
}
}
?>
Output: rat doesn't exist
you need to check exist or not like this
<?php
$A=['dog', 'cat', 'monkey'];
$B=['cat', 'rat', 'dog', 'monkey'];
foreach($A as $animal) {
if(in_array($animal, $B)) {
echo "exist";
}
else{
echo 'not exist';
}
}
?>
Try the below to check which exist and which doesn't.
<?php
$A=['dog', 'cat', 'monkey'];
$B=['cat', 'rat', 'dog', 'monkey'];
foreach($A as $animal) {
if(in_array($animal, $B)) {
echo "$animal exists in \$B<br/>";
}
else{
echo "$animal does not exist in \$B<br/>";
}
}
?>
Your condition is true every time because all elements of array A exists in array B. Try adding a new element and then see.
<?php
$A=['dog', 'cat', 'monkey', 'kite'];
$B=['cat', 'rat', 'dog', 'monkey'];
foreach($A as $animal) {
if(!in_array($animal, $B)) {
echo "$animal doesn't exist<br>";
} else {
echo "$animal exist<br>";
}
?>
Think the logic first before implementing a program.
<?php /*try this function,,
array_key_exists(array_key, array_name)*/
$A=['dog', 'cat', 'monkey'];
$B=['cat', 'rat', 'dog', 'monkey'];
foreach($A as $animal) {
if(array_key_exists($animal, $B)) {
echo "$animal doesn't exist<br>";
} else{echo"$animal doesnot exit<br>";}
$B, so of course the if loop gets never called. What did you expect?