How to lower cyclomatic complexity of switch with 11 cases - php

Question

I have to check if a value is withing a range (0..9, 10..19..up to 100) and return a value depending on the range. The cyclomatic complexity of my function is 12 and I need to lower it to at least 9.
I'm really at a loss here.
I wanted to use an associative array (to use like a Dictionary or a Hash table), but I don't think it works with ranges and I don't want to have an array explicitly declared with 100 entries!
$value = 23;
switch(true) {
case in_array($value, range(0,9)):
return -10;
break;
case in_array($value, range(10,19)):
return -7;
break;
case in_array($value, range(20,29)):
return -5;
break;
case in_array($value, range(30,39)):
return 3;
break;
case in_array($value, range(40,49)):
return 4;
break;
case in_array($value, range(50,59)):
return 5;
break;
case in_array($value, range(60,69)):
return 6;
break;
case in_array($value, range(70,79)):
return 7;
break;
case in_array($value, range(80,89)):
return 8;
break;
case in_array($value, range(90,99)):
return 9;
break;
case in_array($value, range(100,100)):
return 10;
break;
default:
return 0;
break;
}
Can someone help? Is there a simpler way to do that?
TIA

Answer 1

Since the steps are regulary each 10, you can perform an integer division by 10 and lookup the corresponding values in an array:
function theFunc(int $i)
{
return ($i<0 || $i>100) ? 0 : [-10, -7, -5, 3, 4, 5, 6, 7, 8, 9, 10][(int)($i/10)];
}
for($i = -1 ; $i <= 101 ; $i++)
var_dump([$i, theFunc($i)]);

Answer 2

You can just use integer division if the number is greater than 30. You also don't need break; if you are returning, as it will already stop code execution.
switch(true) {
case in_array($value, range(0,9)):
return -10;
case in_array($value, range(10,19)):
return -7;
case in_array($value, range(20,29)):
return -5;
case in_array($value, range(30,100)):
return intdiv($value, 10);
default:
return 0;
}