Simpler way to check if variable is not equal to multiple string values?

Question

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.

Solution 1

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

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

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

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

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}
?>

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