Pair tuple data type in Go

Question

While doing the final exercise of the Tour of Go  I decided I needed a queue of  string  int  pairs  That s easy enough   type job struct       url string     depth int    queue    make chan job  queue  lt - job url  depth    But this got me thinking  are there built-in pair tuple data types in Go  There is support for returning multiple values from a function  but AFAICT  the multiple value tuples produced are not first-class citizens in Go s type system  Is that the case   As for the  what have you tried  part  the obvious syntax  from a Python programmer s POV   queue    make chan  string  int     didn t work

User · Answer

You can do this   It looks more wordy than a tuple  but it s a big improvement because you get type checking   Edit  Replaced snippet with complete working example  following Nick s suggestion   Playground link  http   play golang org p RNx otTFpk  package main  import  fmt   func main         queue    make chan struct  string  int       go sendPair queue      pair     lt -queue     fmt Println pair string  pair int     func sendPair queue chan struct  string  int         queue  lt - struct  string  int   http       3      Anonymous structs and fields are fine for quick and dirty solutions like this   For all but the simplest cases though  you d do better to define a named struct just like you did

User · Answer

You could do something like this if you wanted  package main  import  fmt   type Pair struct       a  b interface      func main         p1    Pair  finished   42      p2    Pair 6 1   hello       fmt Println  p1    p1   p2    p2      fmt Println  p1 b   p1 b         But to use the values you ll need a type assertion     s    p1 a  string      now      fmt Println  p1 a   s      However I think what you have already is perfectly idiomatic and the struct describes your data perfectly which is a big advantage over using plain tuples

User · Answer

There is no tuple type in Go  and you are correct  the multiple values returned by functions do not represent a first-class object   Nick s answer shows how you can do something similar that handles arbitrary types using interface     I might have used an array rather than a struct to make it indexable like a tuple  but the key idea is the interface   type   My other answer shows how you can do something similar that avoids creating a type using anonymous structs   These techniques have some properties of tuples  but no  they are not tuples

[go] Pair/tuple data type in Go

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