Go ordered map

[Tong Sun]

Sorry if this  topic has been discussed, but I'm looking for a Go ordered map implementation. 

I've found 

- https://github.com/samdolan/go-ordered-map

- https://github.com/emperorcow/orderedmap

etc

But none seems to be being maintained. 

Anyone has used or can recommend a good Go ordered map implementation? 

Thx

[Michael Jones]

As a curiosity, is an ordered map really a hashtable or is it a different kind of self-organizing search structure? I would look to LLRB trees if order is an issue... (do a Google search for "Sedgewick LLRB") or start here:

https://www.cs.princeton.edu/~rs/talks/LLRB/RedBlack.pdf

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[Egon]

Do you mean ordered map or sorted map... either way, as long as the N is small, then you can use a slice to provide the extra functionality:

1. sorted map https://play.golang.org/p/oLM4u5HwQ6

2. ordered map https://play.golang.org/p/OFXhFyyrmZ

[Tong Sun]

Oh, thanks a lot Egon, 

Your neat and elegant code is very helpful for me to get the idea and get started. 

Just FTA, in case someone is also reading this, more onto sorting the slice, here is my archive from this list:

https://groups.google.com/d/msg/golang-nuts/WV4d-0UTvLo/tJOoqOf9AgAJ

I want to write three different go functions that sorts based on age, name and sal.

The traditional way to achieve this in go (as showcased here and here) is, to :

- declare a named type of slice

- implement 3 methods Len, Less, Swap

- call sort.Sort

(each attribute age, name, sal, needs its own type declaration and 3 method implementations).

Since Go 1.8, we can achieve basically the same with much less boilerplate code (as showcased here and here) :

- implement 1 func "less" having type  func(i, j int) bool

- call sort.Slice

(each attribute age, name, sal, needs its own "less" func).

I suggest the latter.

HTH

Valentin

[Tong Sun]

On Wednesday, August 16, 2017 at 9:20:21 AM UTC-4, Tong Sun wrote:

Oh, thanks a lot Egon, 

Your neat and elegant code is very helpful for me to get the idea and get started. 

Just FTA, in case someone is also reading this, more onto sorting the slice, here is my archive from this list:

That's irrelevant to Egon's solution. Just to make it clear. 

[Sokolov Yura]

I've implemented AVL tree as index for sort.Interface: https://github.com/funny-falcon/go-tree

(It is not strictly index, cause it could Swap elements).

So it could be used in conjunction with same type that is defined for sort.Sort .

среда, 16 августа 2017 г., 3:17:29 UTC+3 пользователь Tong Sun написал: