how to use or in an if statement php code example

Example 1: php conditionals

#Conditionals

<?php
    #Conditionals
    /*
    == equals
    === identical
    < less than
    > greater than
    <= less than or equal to
    >= greate than or equal to
    != not equal to
    !== not identrical
    */
    $num = 5;

    #if($num == 5){
     #   echo '5 passed';
    #}elseif($num == 6){
   #     echo '6 passed';
  #  }else{
 #       echo'did not pass';
#    }

    #nesting If Statements
    
    if($num>4){
        if($num < 10){
            echo "$num passed<br>";
        }
    }
    /*
    Logical operators can be used 
    instead of what is above

    and     &&
    or      ||
    xor          means one has to be true but not both
    */
    if($num >4 && $num <10){
        echo "$num passed using Logical operators";
    }
    /*
    Switch tests for value and then find
    a match and do something
    */
    $favColor = 'pink';

    switch($favColor){
    case 'red':
        echo '<br>Your favorite color is red';
        break;
    case 'green':
        echo '<br>OH NO!! Your favorite color is green';
        break;
    case 'blue':
        echo '<br>Kool!! Your favorite color is blue';
        break;
    default:
        echo '<br>Yikes! Your favorite color is something else';
        
    }

?>

Example 2: php if

<?php
if ($a > $b)
  echo "a is bigger than b";
?>