What is the difference between Switch and IF?

Question

I know this may be simple question but want to know every ones opinion on this.

what is the difference between switch and IF function in PHP?? What I can see is where ever "switch" function uses "IF" function also applies there..correct me if I am wrong..

Or any performance wise difference between two??

Answer 1

Or any performance wise difference between two??

Forget about the performance difference on this level- there may be a microscopic one, but you'll feel it only when doing hundreds of thousands of operations, if at all. switch is a construct for better code readability and maintainability:

switch ($value) 
 {
 case 1:   .... break;
 case 2:   .... break;
 case 3:   .... break;
 case 4:   .... break;
 case 5:   .... break;
 default:  .... break;
 }

is mostly much more clean and readable than

if ($value == 1) { .... }
elseif ($value == 2) { .... }
elseif ($value == 3) { .... }
elseif ($value == 4) { .... }
elseif ($value == 5) { .... }
else { .... }

Edit: Inspired by Kuchen's comment, for completeness' sake some benchmarks (results will vary, it's a live one). Keep in mind that these are tests that run 1,000 times. The difference for a couple of if's is totally negligeable.

• if and elseif (using ==) 174 µs
• if, elseif and else (using ==) 223 µs
• if, elseif and else (using ===) 130 µs
• switch / case 183 µs
• switch / case / default 215 µs

Conclusion (from phpbench.com):

Using a switch/case or if/elseif is almost the same. Note that the test is unsing === (is exactly equal to) and is slightly faster then using == (is equal to).

Answer 2

If you have simple conditions, like if something equates to something else, then a switch is ideal.

For example, instead of doing the following:

if($bla == 1) {

} elseif($bla == 2) {

} elseif($bla == 3) {

} etc...

It's better to do it like this:

switch($bla) {
  case 1:
    ...
    break;
  case 2:
    ...
    break;
  case 3:
    ...
    break;
  default:
    ...
    break;
}

Alternatively, if you have complex conditions, you should use an if/else.

I think that this is all a matter of opinion though - some people just don't use switch statements at all, and stick with if/else.

Answer 3

No, you are right.
There are not much difference between these statements.
You may use one you like.

Just bear in mind that if you have to use more than 3-4 consecutive conditions - that means you most likely have design faults.

Usually you can substitute such a statement with a loop or with more clear application design.