What is the best way to test for an empty string in Go?

string go is-empty
Richard picture Richard · Sep 3, 2013 · Viewed 265.4k times · Source

Which method is best (more idomatic) for testing non-empty strings (in Go)?

if len(mystring) > 0 { }

Or:

if mystring != "" { }

Or something else?

Answer

ANisus picture ANisus · Sep 3, 2013

Both styles are used within the Go's standard libraries.

if len(s) > 0 { ... }

can be found in the strconv package: http://golang.org/src/pkg/strconv/atoi.go

if s != "" { ... }

can be found in the encoding/json package: http://golang.org/src/pkg/encoding/json/encode.go

Both are idiomatic and are clear enough. It is more a matter of personal taste and about clarity.

Russ Cox writes in a golang-nuts thread:

The one that makes the code clear.
If I'm about to look at element x I typically write
len(s) > x, even for x == 0, but if I care about
"is it this specific string" I tend to write s == "".

It's reasonable to assume that a mature compiler will compile
len(s) == 0 and s == "" into the same, efficient code.
...

Make the code clear.

As pointed out in Timmmm's answer, the Go compiler does generate identical code in both cases.

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