How to count the number of unique elements by group in a table

19 views (last 30 days)
Hi,
How can I count the number of unique elements by group in a table and save the answer in a vector ?
% Create table
name = {'A', 'A', 'A', 'B', 'B', 'B', 'C', 'C', 'C'}.';
type = {'AA', 'BB', 'CC', 'BB', 'BB', 'BB', 'AA', 'CC', 'CC'}.';
t = table(name, type);
For example, in the table here the number of unique 'type' per 'name' would yield 3, 1, 2 (i.e. 3 'unique 'types' for name A, 1 'unique 'types' for name B, and 2 'unique 'types' for name C,)
Thank you,

Accepted Answer

Blue
Blue on 8 Aug 2019
name = {'A', 'A', 'A', 'B', 'B', 'B', 'C', 'C', 'C'}.';
type = {'AA', 'BB', 'CC', 'BB', 'BB', 'BB', 'AA', 'CC', 'CC'}.';
t = table(name, type);
n_type = rowfun(@(v) numel(unique(v)), t, 'GroupingVariables', 'name', 'InputVariables', 'type')

More Answers (1)

KALYAN ACHARJYA
KALYAN ACHARJYA on 8 Aug 2019
Edited: KALYAN ACHARJYA on 8 Aug 2019
name = {'A', 'A', 'A', 'B', 'B', 'B', 'C', 'C', 'C'}.';
type = {'AA', 'BB', 'CC', 'BB', 'BB', 'BB', 'AA', 'CC', 'CC'}.';
t = table(unique(name), unique(type))
Command Window:
t =
3×2 table
Var1 Var2
_ ____
'A' 'AA'
'B' 'BB'
'C' 'CC'
Unique Elements
>> H=height(t)
H =
3
  1 Comment
Blue
Blue on 8 Aug 2019
Thank you kindly for your answer but it doesnt quite do what I want. I need a count of the unique elements per group, in this case 3,1,2.

Sign in to comment.

Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!