[Map/Set] Add an .update() method, a la Python?
On Jun 27, 2013, at 4:47 PM, Tab Atkins Jr. wrote:
Has it been discussed yet to add an .update() method to Map and Set, a la Python, which take an iterable (yielding [key, value] for Map, and just value for Set) and add the iterable's entries to the Map/Set?
It desugars easily:
Map.prototype.update = function(iter) { Map(iter).forEach((v,k)=>this.set(k,v)); }; Set.prototype.update = function(iter) { Set(iter).forEach(v=>this.add(v)); };
I've used this kind of dict/set addition in Python plenty, and added the method to my Map polyfill that I use for some personal projects.
Thoughts?
for (let [k,v] of iter) myMap.set(k,v)
On Thu, Jun 27, 2013 at 5:06 PM, Allen Wirfs-Brock <allen at wirfs-brock.com> wrote:
On Jun 27, 2013, at 4:47 PM, Tab Atkins Jr. wrote:
Has it been discussed yet to add an .update() method to Map and Set, a la Python, which take an iterable (yielding [key, value] for Map, and just value for Set) and add the iterable's entries to the Map/Set?
It desugars easily:
Map.prototype.update = function(iter) { Map(iter).forEach((v,k)=>this.set(k,v)); }; Set.prototype.update = function(iter) { Set(iter).forEach(v=>this.add(v)); };
I've used this kind of dict/set addition in Python plenty, and added the method to my Map polyfill that I use for some personal projects.
Thoughts?
for (let [k,v] of iter) myMap.set(k,v)
Right, it's easy to write yourself, but it's a common enough operation that Python found it worthwhile to add, and I found it useful for my own purposes.
In particular, I like that it just returns the modified map/set, so it's easy to chain with, or to immediately return.
It's basically equivalent to dest.splice(-1, 0, ...source) for Arrays. (Or concat, if you ignore the fact that it doesn't alter the destination.)
On Thu, Jun 27, 2013 at 8:11 PM, Tab Atkins Jr. <jackalmage at gmail.com>wrote:
On Thu, Jun 27, 2013 at 5:06 PM, Allen Wirfs-Brock <allen at wirfs-brock.com> wrote:
On Jun 27, 2013, at 4:47 PM, Tab Atkins Jr. wrote:
Has it been discussed yet to add an .update() method to Map and Set, a la Python, which take an iterable (yielding [key, value] for Map, and just value for Set) and add the iterable's entries to the Map/Set?
It desugars easily:
Map.prototype.update = function(iter) { Map(iter).forEach((v,k)=>this.set(k,v)); }; Set.prototype.update = function(iter) { Set(iter).forEach(v=>this.add(v)); };
I've used this kind of dict/set addition in Python plenty, and added the method to my Map polyfill that I use for some personal projects.
Thoughts?
for (let [k,v] of iter) myMap.set(k,v)
Right, it's easy to write yourself, but it's a common enough operation that Python found it worthwhile to add, and I found it useful for my own purposes.
My gut reaction was the same as Allen's, but Ruby's Hash also has update(other_hsh) (though it is the same as merge!)
In particular, I like that it just returns the modified map/set, so it's easy to chain with, or to immediately return.
I was wondering about this while reading your OP, but you're not returning anything in that "desugaring". Anyway, I agree with this reasoning.
On Thu, Jun 27, 2013 at 5:26 PM, Rick Waldron <waldron.rick at gmail.com> wrote:
On Thu, Jun 27, 2013 at 8:11 PM, Tab Atkins Jr. <jackalmage at gmail.com> wrote:
In particular, I like that it just returns the modified map/set, so it's easy to chain with, or to immediately return.
I was wondering about this while reading your OP, but you're not returning anything in that "desugaring". Anyway, I agree with this reasoning.
Whoops, I left that out accidentally. Modified (also to use Allen's for-of rather than forEach):
Map.prototype.update = function(iter) { for([k,v] of iter) this.set(k,v); return this; }; Set.prototype.update = function(iter) { for(v of iter) this.add(v); return this; };
On Thu, Jun 27, 2013 at 8:30 PM, Tab Atkins Jr. <jackalmage at gmail.com>wrote:
Whoops, I left that out accidentally. Modified (also to use Allen's for-of rather than forEach):
I agree with this and I think these should be added to the pool of methods to consider for Map and Set. The "pool" I refer to includes, but is not limited to:
- union
- intersect
- difference
- update (as of now)
I've found it satisfyingly idiomatic to call this addEach (for both maps
and other collections) in my work on Collections.
On Thu, Jun 27, 2013 at 8:37 PM, Rick Waldron <waldron.rick at gmail.com>wrote:
On Thu, Jun 27, 2013 at 8:30 PM, Tab Atkins Jr. <jackalmage at gmail.com>wrote:
On Thu, Jun 27, 2013 at 5:26 PM, Rick Waldron <waldron.rick at gmail.com> wrote:
On Thu, Jun 27, 2013 at 8:11 PM, Tab Atkins Jr. <jackalmage at gmail.com> wrote:
In particular, I like that it just returns the modified map/set, so it's easy to chain with, or to immediately return.
I was wondering about this while reading your OP, but you're not returning anything in that "desugaring". Anyway, I agree with this reasoning.
Whoops, I left that out accidentally. Modified (also to use Allen's for-of rather than forEach):
Map.prototype.update = function(iter) { for([k,v] of iter) this.set(k,v); return this; }; Set.prototype.update = function(iter) { for(v of iter) this.add(v); return this; };
I agree with this and I think these should be added to the pool of methods to consider for Map and Set. The "pool" I refer to includes, but is not limited to:
- union
- intersect
- difference
- update (as of now)
Sorry, instead of "for Map and Set", I should use the more generic "for iterables" when generalizing, since not all Set methods are relevant to Map objects and not all Map methods are relevant to Set objects.
Has it been discussed yet to add an .update() method to Map and Set, a la Python, which take an iterable (yielding [key, value] for Map, and just value for Set) and add the iterable's entries to the Map/Set?
It desugars easily:
Map.prototype.update = function(iter) { Map(iter).forEach((v,k)=>this.set(k,v)); }; Set.prototype.update = function(iter) { Set(iter).forEach(v=>this.add(v)); };I've used this kind of dict/set addition in Python plenty, and added the method to my Map polyfill that I use for some personal projects.
Thoughts?
Has it been discussed yet to add an .update() method to Map and Set, a la Python, which take an iterable (yielding [key, value] for Map, and just value for Set) and add the iterable's entries to the Map/Set? It desugars easily: Map.prototype.update = function(iter) { Map(iter).forEach((v,k)=>this.set(k,v)); }; Set.prototype.update = function(iter) { Set(iter).forEach(v=>this.add(v)); }; I've used this kind of dict/set addition in Python plenty, and added the method to my Map polyfill that I use for some personal projects. Thoughts? ~TJ