How do i count unique elements in two table columns?

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ahmed obaid
ahmed obaid 2017-6-9
评论： ahmed obaid 2017-6-9
Dear all;
for the following table:which include student name, class and school name ..
std_name class School
A1 1 Art
A2 1 Art
A3 1 Muc
A4 2 muc
A5 3 Art
A6 2 fun
A7 3 fun
A8 4 Muc
...
i need to count : - how many student in every class, then write new table includes the following result as example: class number and how many student in every class, then names of schools... as shown below:
class No. of std School
1 50 Art, Muc
2 30 muc, fun
3 10 Art, fun
4 100 muc
etc..
-

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采纳的回答

Guillaume
Guillaume 2017-6-9
编辑：Guillaume 2017-6-9
Simpler, using rowfun which did exist in R2015a:
out = rowfun(@(school) {strjoin(unique(school), ', ')}, A, ...
'GroupingVariables', 'class', 'InputVariables', 'School')

更多回答（1 个）

Andrei Bobrov
Andrei Bobrov 2017-6-9
编辑：Andrei Bobrov 2017-6-9
A = readtable('A.csv');
A.Properties.VariableNames = {'std_name','class','School'};
[g,ii] = findgroups(A.class);
out = table(ii,accumarray(g,1),splitapply(@(x){strjoin(unique(x),',')},A.School,g),...
'var',{'class','No_of_std','School' });
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Guillaume
Guillaume 2017-6-9
编辑：Guillaume 2017-6-9
You download R2015b like you download any other releases, directly from the mathworks site:
https://www.mathworks.com/downloads/web_downloads/download_release?release=R2015b
To see what's new in R2015b: https://uk.mathworks.com/help/releases/R2015b/matlab/release-notes.html#R2015b
But if you're going to upgrade, you'd be better off moving to the latest version: 2017a
ahmed obaid
ahmed obaid 2017-6-9
Perhaps ... modified code to earlier version.. upgrades is not available currently.. thanks

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