How to compare two array in php - php

Question

while($row = $update_post->fetch_array()){
//Explodes checkbox values
$res = $row['column_name'];
$field = explode(",", $res);
$arr = array('r1','r2,'r3','r4','r5','r6');
if (in_array($arr, $field)) {
echo "<script>alert('something to do')</script>";
}else{
echo "<script>alert('something to do')</script>";
}
}
How to check if value of $arr is equal to the value of $field.
Thank you in Advance.

Answer 1

If you want to match two array than you need to use array_intersect() here.
If you want to check specific value with in_array() than you need to use loop here as:
<?php
$res = $row['column_name'];
$field = explode(",", $res);
$arr = array('r1','r2','r3','r4','r5','r6');
foreach ($arr as $value) {
if(in_array($value, $field)) {
echo "success";
}
else{
echo "failed";
}
}
?>
According to manual: in_array — Checks if a value exists in an array
Also note that, you have a syntax error in your array:
$arr = array('r1','r2,'r3','r4','r5','r6'); // missing quote here for r2
Update:
If you want to use array_intersect() than you can check like that:
<?php
$arr1 = array('r1','r2');
$arr2 = array('r1','r2','r3','r4','r5','r6');
$result = !empty(array_intersect($arr1, $arr2));
if($result){
echo "true";
}
else{
echo "false";
}
?>
DEMO
Update 2:
If you want to check which value are you getting by using array_intersect() than you can use like:
<?php
$arr1 = array('r2');
$arr2 = array('r1','r2','r3','r4','r5','r6');
$result = array_intersect($arr1, $arr2);
if(count($result)){
echo "Following ID(s) found: ".implode(",",$result);
}
?>
DEMO

Answer 2

compare two array by array_intersect then check with count to know matches array value has...
array_intersect
Compare the values of two arrays, and return the matches:
while($row = $update_post->fetch_array()){
//Explodes checkbox values
$res = $row['column_name'];
$field = explode(",", $res);
$arr = array('r1','r2','r3','r4','r5','r6');
if (count(array_intersect($arr, $field)) > 0) {
echo "<script>alert('duplicate array')</script>";
}else{
echo "<script>alert('something to do')</script>";
}
}