Simpler way to check if variable is not equal to multiple string values?
PhpIf StatementConditional StatementsPhp Problem Overview
Current Codes:
<?php
// See the AND operator; How do I simplify/shorten this line?
if( $some_variable !== 'uk' && $some_variable !== 'in' ) {
// Do something
}
?>
And:
<?php
// See the OR operator; How do I simplify/shorten this line?
if( $some_variable !== 'uk' || $some_variable !== 'in' ) {
// Do something else
}
?>
Is there a simpler (i.e. shorter) way to write the two conditions?
NOTE: Yes, they are different, and I am expecting different ways to shorten the codes.
Php Solutions
Solution 1 - Php
For your first code, you can use a short alteration of the answer given by
@ShankarDamodaran using in_array():
if ( !in_array($some_variable, array('uk','in'), true ) ) {
or even shorter with [] notation available since php 5.4 as pointed out by @Forty in the comments
if ( !in_array($some_variable, ['uk','in'], true ) ) {
is the same as:
if ( $some_variable !== 'uk' && $some_variable !== 'in' ) {
... but shorter. Especially if you compare more than just 'uk' and 'in'. I do not use an additional variable (Shankar used $os) but instead define the array in the if statement. Some might find that dirty, i find it quick and neat :D
The problem with your second code is that it can easily be exchanged with just TRUE since:
if (true) {
equals
if ( $some_variable !== 'uk' || $some_variable !== 'in' ) {
You are asking if the value of a string is not A or Not B. If it is A, it is definitely not also B and if it is B it is definitely not A. And if it is C or literally anything else, it is also not A and not B. So that statement always (not taking into account schrödingers law here) returns true.
Solution 2 - Php
You can make use of in_array() in PHP.
$os = array("uk", "us"); // You can set multiple check conditions here
if (in_array("uk", $os)) //Founds a match !
{
echo "Got you";
}
Solution 3 - Php
An alternative that might make sense especially if this test is being made multiple times and you are running PHP 7+ and have installed the Set class is:
use Ds\Set;
$strings = new Set(['uk', 'in']);
if (!$strings->contains($some_variable)) {
Or on any version of PHP you can use an associative array to simulate a set:
$strings = ['uk' => 1, 'in' => 1];
if (!isset($strings[$some_variable])) {
There is additional overhead in creating the set but each test then becomes an O(1) operation. Of course the savings becomes greater the longer the list of strings being compared is.
Solution 4 - Php
If you're planning on building a function in the if statement, I'd also advise the use of in_array. It's a lot cleaner.
If you're attempting to assign values to variables you can use the if/else shorthand:
$variable_to_fill = $some_variable !== 'uk' ? false : true;
Solution 5 - Php
You need to multi value check. Try using the following code :
<?php
$illstack=array(...............);
$val=array('uk','bn','in');
if(count(array_intersect($illstack,$val))===count($val)){ // all of $val is in $illstack}
?>
Solution 6 - Php
You may find it more readable to reverse your logic and use an else statement with an empty if.
if($some_variable === 'uk' || $another_variable === 'in'){}
else {
// This occurs when neither of the above are true
}
Solution 7 - Php
I like the code used by Habchi in comments
if(!($some_variable === 'uk' || $another_variable === 'in')){//do}
Solution 8 - Php
Some basic regex would do the trick nicely for $some_variable !== 'uk' && $some_variable !== 'in':
if(!preg_match('/^uk|in$/', $some_variable)) {
// Do something
}