How to use a list to label a BarChart

Question

I'm trying to add labels to the BarChart I have generated from a Dataset however, I seem to be stuck on a couple of points. Firstly given the below syntax, where am I supposed to add in the BarChart options?

test = Dataset[{
    <|"num" -> 0|>, <|"num" -> 0|>, <|"num" -> 1|>, <|"num" -> 2|>, <|
     "num" -> 0|>, <|"num" -> 0|>, <|"num" -> 1|>, <|"num" -> 2|>, <|
     "num" -> 2|>, <|"num" -> 1|>, <|"num" -> 2|>, <|"num" -> 3|>, <|
     "num" -> 3|>, <|"num" -> 5|>, <|"num" -> 4|>, <|"num" -> 5|>, <|
     "num" -> 0|>, <|"num" -> 5|>}];
test[Counts, #num &]
test[Counts /* BarChart, #num &]

Secondly, I know I can add in

...,ChartLabels->{"list","of","things"} ...

but I really want to pass the output of the Counts so that I can do it programatically for a number of different Datasets.

TIA

Answer 1

You need to create a Pure Function with BarChart that takes the results of your query and has the options you want. Use Keys to get the chart labels from Counts

Inline

test[Counts /* (BarChart[#, ChartLabels -> Keys[#]] &), #num &]

Defined

myChart = BarChart[#, ChartLabels -> Keys[#]] &;
test[Counts /* myChart, #num &]

Both methods give

Hope this helps.

Note: You can also replace Keys[#] with Automatic since BarChart understands Associations. In fact using Automatic is better if you have multiple levels.

test[Counts /* (BarChart[#, ChartLabels -> Automatic] &), #num &]

and

myChart = BarChart[#, ChartLabels -> Automatic] &;
test[Counts /* myChart, #num &]