If or switch( Which one should I use ...)

Technical Discussion
1

The behavior of “if” and “switch” is almost the same.
Should I use “if” and “switch” in your opinion, considering many things?
(* Some characters were deleted because my thoughts were unsatisfactory.)

2

For a discussion of the control structures available in Go and how to use them, see https://golang.org/doc/effective_go.html#control-structures

Don’t decide to use if or switch based on performance.

3

If there is few options, i prefer “if”. If there is many options I prefer “switch”. Mostly because it is more readable and you can manage several options in one line ( = fewer lines of code)

4

Maybe this is obvious, but for completeness’ sake, I’ll say that I use if whenver I only need to check for a single condition:

// do stuff

if somePredicate() {
    // do stuff
}

// keep doing stuff

I try hard to avoid writing else but I don’t really have a good reason!

I never use else if. I will always replace it with a switch:

switch {
case predicateA():
    // do something
case predicateB():
    // do something
default:
    // do something
}

instead of:

if predicateA() {
    // do stuff
} else if predicateB() {
    // do stuff
} else {
    // do stuff
}
2 Likes
5

One other situation that prompted me to use switch rather than if recently was something like this:

type Thing struct {
    t1 int
    t2 int
}
func DoSomething(params ...int) {
    t := Thing{0, 0}
    switch len(params) {
    case 2:
        t.t2 = params[1]
        fallthrough
    case 1:
        t.t1 = params[0]
    }
    // do something with t now
}

This way I only initialize t once, and I capture both cases where params is 1 or 2 in length by making use of fallthrough. Switch might also be more readable in cases where you have specific “cases” you are dealing with (like… if you’ve only defined small, medium, and large) then it makes it a little more clear that these are the only cases you’ll “ever” plan to deal with whereas that just isn’t as clear with if.

That said, I think I use if more than switch. Just a matter of readability and the particularity of your specific case.

6

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