strange beahviour with a php switch? - php

Question

A sample of what I'm trying to do will be more explicit:
var_dump($opti_point); //int 0
if ($opti_point>=0 && $opti_point < 25) echo 'good';//echoing good
switch ($opti_point) {
case ($opti_point>= 0 && $opti_point < 25):
$test = 0;
break;
case ($opti_point >= 25 && $opti_point < 50):
echo 'we are in this case'; // This case is called !
$test = 2;
break;
default:
test = 0;
break;
}
Is there a trick here ?
thx

Answer 1

You cannot put comparisons inside "case" unfortunately...
A switch is only used when a value can have one of a limited number of values like so:
switch ( $val ) {
case 1:
echo "Got 1";
break;
case 2:
echo "Got 2";
break;
default:
echo "Got invalid value";
}
A workaround would be to use:
switch (true) {
case ($opti_point>= 0 && $opti_point < 25):
$test = 0;
break;
case ($opti_point >= 25 && $opti_point < 50):
echo 'we are in this case';
$test = 2;
break;
default:
test = 0;
break;
}
Which will work, but is a bit ugly...
Also, you're missing a single quote in echo we are in this case'; which should be echo 'we are in this case';
You should be using an if instead =)

Answer 2

You need to change the switch argument to true of false if you do comparison liek that in the cases.

Answer 3

You are not comparing what you think you are comparing. This is the code I think you want.
var_dump($opti_point); //int 0
if ($opti_point>=0 && $opti_point < 25) {
$test = 0;
echo 'You are now here!';
} elseif ($opti_point >= 25 && $opti_point < 50) {
$test = 2;
} else {
test = 0;
}
In your example, you are comparing the result of the logical statement...
($opti_point>=0 && $opti_point < 25) // true
To the value of $opti_point
0 // false
So PHP is actually converting what you think in an integer into a boolean to compare it with the result of the conditional statement.

Answer 4

I think that's a very bad way to use a switch statement, you should not put conditional sentences in the cases... In fact, I'm sure that that would be illegal in other languages and I'm not sure that it should work in PHP. Use a number of concatenated if-else conditions instead:
if ($i == 0) {
echo "i equals 0";
} elseif ($i == 1) {
echo "i equals 1";
} elseif ($i == 2) {
echo "i equals 2";
}

Answer 5

I'll go true the code with you
var_dump($opti_point); //int 0 , or false --- you should use TRUE
if ($opti_point>=0 && $opti_point < 25) echo 'good';//echoing good
switch ($opti_point) { // chose the case that is $opti_point (0 or false)
case ($opti_point>= 0 && $opti_point < 25): // true, so go to next
$test = 0;
break;
case ($opti_point >= 25 && $opti_point < 50): //false si this is the wan I pick
echo 'we are in this case'; // This case is called !
$test = 2;
break; // ingore the rest
default:
test = 0;
break;
}
you should use TRUE in the switch

Answer 6

if this is the exact code then try this
var_dump($opti_point); //int 0
if ($opti_point>=0 && $opti_point < 25) echo 'good';//echoing good
switch ($opti_point) {
case ($opti_point>= 0 && $opti_point < 25):
$test = 0;
break;
case ($opti_point >= 25 && $opti_point < 50):
echo 'we are in this case'; // This case is called !
$test = 2;
break;
default:
$test = 0;
break;
}

Answer 7

You have a misunderstanding on how switch-case works. Case DOES NOT TEST YOUR EXPRESSION TO BE boolean TRUE!
It compares its value to 'switch' value!
Here is an explanation:
$opti_point>= 0 && $opti_point < 25 evalutes to true which integer representation is 1 and since PHP can deal with types on it's own, it turnes true to 1 and compares it with value in switch which is 0
$opti_point >= 25 && $opti_point < 50 evaluates to false which is 0 as integer, so... that's your case ;)