topic Re: count(distinct val) in Discussions

count(distinct val)

unbbmas — Wed, 10 Jul 2013 10:07:31 GMT

Hello All,

Any function in Jmp similar to count distinct in sql?

Examples:

How can I obtain the values of count distinct subjectsid in a new column in these tables with functions?

Thanks

TABLA 1

subjectid count distinct subjectid

a 5

b 5

c 5

a 5

b 5

d 5

e 5

TABLA 2

subjectid count distinct subjectid

a 3

b 3

c 3

a 3

Re: count(distinct val)

Anonymous — Wed, 10 Jul 2013 14:42:31 GMT

I can't readily think of a way to have a formula accomplish a COUNT DISTINCT. However, you can get the value via a couple Table Summaries and a Table Join, which you can then code into JSL if you choose.

In Table A, Select Table --> Summary, Group By subjectid, select OK. In the summary table, select Table --> Summary, Select subjectid, and select "N" under Statistics, select OK. In the new table, delete the "N Rows" Column. Go back to the first table, and select Table --> Join. Then select to join with the last summary table with matching specification of Cartesian Join, then select OK. The distinct count will show up in your original table.

If you were to script it:

dt = Current Data Table();

sumdt = dt << Summary( Group( :subjectid ), invisible );

sumsumdt = sumdt << Summary( Group, N( :subjectid ), invisible );

count_distinctdt = dt << Join(

With( sumsumdt ),

Cartesian Join

);

count_distinctdt << delete columns("N Rows");

column("N(subjectid)") << set name("count distinct subjectid");

sumsumdt << close window;

sumdt << close window;

close(dt,no save);

Re: count(distinct val)

XanGregg — Thu, 11 Jul 2013 20:30:03 GMT

A simple though inefficient formula is:

Summation( i = 1, N Row(), :subjectid == :subjectid)

It takes advantage of the fact that true is 1 and false is 0, so summing up the comparisons gives a count.

Using the Table Summary method as TheChadd describes or using JSL will be faster if the table is really big.

Re: count(distinct val)

Beaux — Thu, 20 Jul 2017 12:28:08 GMT

I found this aggregate function useful:

N Categories()

Re: count(distinct val)

Mark_Bailey — Thu, 20 Jul 2017 13:45:11 GMT

Sadly, I can't find the N Categories() function in the Scripting Index.

Luckily I would be satisfied with any of the previous solutions.

// Open an example
dt = Open( "$SAMPLE_DATA/Big Class.jmp" );

// Use the Tables > Summary command approach
dt << Summary(
	Group( :age ),
	Freq( "None" ),
	Weight( "None" )
);

// Use the Analyze > Tabulate approach
dt << Tabulate(
	Show Control Panel( 0 ),
	Add Table( Row Table( Grouping Columns( :age ) ) )
);

// Use the JSL Summarize() function approach
Summarize(
	group = By( :age ),
	n = Count()
);

Re: count(distinct val)

Jeff_Perkinson — Thu, 20 Jul 2017 18:29:48 GMT

I was puzzled by @Beaux's response as well but I think he's referring to the N Categories summary statistic in Tables->Summary.

Re: count(distinct val)

Beaux — Thu, 20 Jul 2017 20:16:02 GMT

Strange that that function is not available in the formula editor (statistical) or JSL... Maybe next version.

Re: count(distinct val)

hogi — Sat, 28 Oct 2023 20:16:14 GMT

As @Jeff_Perkinson says - really puzzling that there is a N categories functionality in Jmp - but that it's restricted to Tables/Summary ?!?

If other users are interested as well to have N Categories not just in the Tables/Summary Platform, but also via JSL ...
- here is the wish:

Re: count(distinct val)

hogi — Sat, 03 May 2025 14:56:34 GMT

Tables/ Summary:

Tabulate:

Header Statistics:

Col N Categories: ~~NOPE~~ -> soon *)

Graph Builder: ~~NOPE~~ -> soon *)

@Jeff_Perkinson , whom do we have to convince to get it implemented in JMP18.1?

*) edit: see below : )

Re: count(distinct val)

hogi — Wed, 31 Jul 2024 11:50:42 GMT

Re: count(distinct val)

hogi — Sat, 03 May 2025 14:55:31 GMT

JMP19 will provide a new function to calculate Col N Categories - actually: Col N Unique()
https://community.jmp.com/t5/JMP-Wish-List/Col-N-Categories/idc-p/870972/highlight/true#M7292

... and via the new column menu it will be available in every report - like Graph Builder.