topic Re: Merge two dictionaries into one in ArcGIS Dashboards Questions

Merge two dictionaries into one

ToddLusk — Wed, 08 Dec 2021 22:07:31 GMT

I have two dictionaries that I would like to merge into a combined one with the "values" added together (see below). The dictionaries are the results of "Summary Counts" of two different columns of data in a hosted feature layer. Here are the dictionaries:

d1 = {"A":10, "B":20, "C":30}

d2 = {"A":1, "B":14, "D":3, "E":5}

I would like to end up with something like:

d3 = {"A":11, "B":34, "C":30, "D":3, "E":3}

As you can see, the dictionary "keys" may not be the same between the two summaries every time. Ultimately, I want to use the combined summary (i.e., the data in"d3") in a Serial Chart in a Dashboard. I'm struggling with how to compare the two dictionaries and check for corresponding keys in each.

Re: Merge two dictionaries into one

jcarlson — Thu, 09 Dec 2021 02:56:17 GMT

Let's solve this with a custom function! For each key in the input dicts, we need to see if the key already exists. If it doesn't, add it as a new key to the output; if it does, add the values together.

var d1 = {"A":10, "B":20, "C":30} var d2 = {"A":1, "B":14, "D":3, "E":5} function dict_merge(dicts_array){ // Empty dict for output var out_dict = {} // Loop over array of input dicts for(var dict in dicts_array){ // Loop over keys in dict for(var d in dicts_array[dict]){ // Add / sum dict value depending on presence of key in out_dict if(!HasKey(out_dict, d)){ out_dict[d] = dicts_array[dict][d] } else { out_dict[d] += dicts_array[dict][d] } } } return out_dict } dict_merge([d1, d2])

And the output:

The best part is, a custom function like this can be used anywhere else you might need it, and is written in such a way that any number of dicts can be supplied, and the output will still work.

Re: Merge two dictionaries into one

ToddLusk — Thu, 09 Dec 2021 11:04:55 GMT

Awesome, thank you so much! I had the "logic" right in my head but couldn't quite figure out the syntax.