What is the idiomatic Go equivalent of C's ternary operator?

Question

In C/C++ (and many languages of that family), a common idiom to declare and initialize a variable depending on a condition uses the ternary conditional operator :

int index = val > 0 ? val : -val 

Go doesn't have the conditional operator. What is the most idiomatic way to implement the same piece of code as above ? I came to the following solution, but it seems quite verbose

var index int  if val > 0 {     index = val } else {     index = -val } 

Is there something better ?

Answer 1

As pointed out (and hopefully unsurprisingly), using if+else is indeed the idiomatic way to do conditionals in Go.

In addition to the full blown var+if+else block of code, though, this spelling is also used often:

index := val if val <= 0 {     index = -val } 

and if you have a block of code that is repetitive enough, such as the equivalent of int value = a <= b ? a : b, you can create a function to hold it:

func min(a, b int) int {     if a <= b {         return a     }     return b }  ...  value := min(a, b) 

The compiler will inline such simple functions, so it's fast, more clear, and shorter.

Answer 2

No Go doesn't have a ternary operator, using if/else syntax is the idiomatic way.

Why does Go not have the ?: operator?

There is no ternary testing operation in Go. You may use the following to achieve the same result:

if expr {     n = trueVal } else {     n = falseVal } 

The reason ?: is absent from Go is that the language's designers had seen the operation used too often to create impenetrably complex expressions. The if-else form, although longer, is unquestionably clearer. A language needs only one conditional control flow construct.

— Frequently Asked Questions (FAQ) - The Go Programming Language