Question

I don t understand what s happening here. Logically, it doesn t make any sense to me.

<?php
$level = 0;

switch ($level) {

  case $level > 80: $answer =  high ; break;
  case $level > 60: $answer =  moderate-to-high ; break;
  case $level > 40: $answer =  moderate ; break;
  case $level > 20: $answer =  low-to-moderate ; break;
  default: $answer =  low ; break;
}   
echo $answer;
?>

When $level == 0, it returns "high". This doesn t make any sense to me. Can someone explain what s happening here?

Answer 1

Change switch ($level) to switch (true) and this will work.

switch statements perform equality tests on the values in the cases. PHP is evaluating your > comparisons, so case $level > 80 becomes case false. false is considered to be equal to 0, so the first case matches.

Answer 2

The quantity after the case needs to be just the value, not a boolean expression. I m guessing that PHP is evaluating case $level > 80 as case ($level > 80) which is becoming case 0 (i.e., false, since $level is indeed NOT less than 80) and so you re matching the first case.

Answer 3

Are you sure you can do this in php?

I just checked the manual of switch and you have to provide a distinct value.

I think if you can write it again into something like:

$levelDivTwenty = intval($level/20);
$levelDivTwenty = ($levelDivTwenty>4)?4:$levelDivTwenty;

and then case on that.

switch ($levelDivTwenty) {
  case 4: //same as $level > 80 before...
  case 3: //>60 etc...
}

Answer 4

As others have pointed out you can t use switch like that, but how about defining it like this:

<?
$level = 21;
$answers = array( low ,  low-to-moderate ,
                  moderate ,  moderate-to-high ,  high );

echo $answers[intval(($level-1)/20)];
?>

Note: If $level = 0, then expression inside intval() will be -1/20, which is less then -1 and therefore will be rounded to 0.

Answer 5

This isn t really how switch is intended to be used. It s to evaluate for a specific value.

Use an If/else if here, instead of complicating your life to make a switch work like one.

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