How do I check for an empty slice?

go slice
Kshitiz Sharma picture Kshitiz Sharma · Jul 1, 2016 · Viewed 81.6k times · Source

I am calling a function that returns an empty array if there are no values.

When I do this it doesn't work:

if r == [] {
    fmt.Println("No return value")            
}

The work around I'm using is:

var a [0]int
if r == a {
    fmt.Println("No return value")            
}

But declaring a variable just to check the return value doesn't seem right. What's the better way to do this?

Answer

Simone Carletti picture Simone Carletti · Jul 1, 2016

len() returns the number of elements in a slice or array.

Assuming whatever() is the function you invoke, you can do something like:

r := whatever()
if len(r) > 0 {
  // do what you want
}

or if you don't need the items

if len(whatever()) > 0 {
  // do what you want
}

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