I found this problem when I was using `if-else-if-...

# getting-started

[SeniorZhai]

I found this problem when I was using if-else-if-else

[Sam]

This is just an order of operations thing

[Sam]

adding parentheses helps to clarify what’s going on

[Sam]

if (random == 0) {
    1L
} else (if (random == 1) {
    "1"
} else {
    "2"
}.apply {
    println(this)
})

[Sam]

Everything after the first else is a single expression

[Michael de Kaste]

chained if-else statements have been discussed before, but consider using a when statement when you have multiple conditions 🙂

[Rob Elliot]

So his first was equivalent to this?

if (random == 0) {
    1L
} else {
    if (random == 1) {
        "1"
    } else {
        "2"
    }.apply {
        println(this)
    }
}

[Rob Elliot]

Whereas what he was expecting was this:

(
    if (random == 0) {
        1L
    } else if (random == 1) {
        "1"
    } else {
        "2"
    }
).apply {
    println(this)
}

[SeniorZhai]

Is this a feature of kotlin? I'm not sure it's the same with other languages.

[Sam]

Well, in many languages if isn’t an expression. It might be more interesting to compare it to the ternary operator, e.g.

random == 0 ? 1L : random == 1 ? "1" : "2"

[Rob Elliot]

Following up on Michael de Kaste's observation, this is the most readable, terse and least unexpected way of expressing it:

when (random) {
    0 -> 1L
    1 -> "1"
    else -> "2"
}.apply {
    println(this)
}

[Rob Elliot]

That was interesting, thanks all - I wasn't aware of that order of precedence in if / else expressions.

[Sam]

The basic principle of `if`/`else` is:

if (condition) expr1 else expr2

so what looks like else if is actually not a ‘real’ language construct, it’s just an else where expr2 happens to be another if expression

[Albert Chang]

https://youtrack.jetbrains.com/issue/KT-16275/A-cascade-if-is-not-a-single-expression-hence-issues-with-dot-calls