Formatting strings with %q in go

1-minute read
technical
go

TIL you can use %d in Printf statements (and its friends, like Fatalf/Errorf) when printing strings/runes.

What it does is:

  • Escapes any special characters
  • Add quotes around it (single if it’s a single rune)

I really like how it adds quotes around the string. I’ve had innumerous times when a go program was supposed to printed something (mostly likely in errors), but since the string was empty, it didn’t print anything.

For example,

1

Error. Invalid URL:

Which always takes me a while to notice. By having an error like

1

Error. Invalid URL: ""

It makes it clear how somehow an empty string is being passed.

Beware that his only works for strings (and runes) though.

Example can be found in the go playground.