strcmp and rows of dataset table

i have a text dataset with 4 columns and n rows : cl1 cl2 cl3 cl4 i want to know how can i use strcmp() to show which rows are with the same CL2 and CL3 (no CL2=CL3)for example ,according to the dataset below i want to show row1 and row4 , becouse they have same cl2 and cl3,

cl1  cl2  cl3  cl4
---------------------------
a  b  c  d
d  j  h  n
s  b  v  y
q  b  c  g

and as i said dataset has "n" rows so some rows have same CL2-Cl3 and... i want to make domains, for example Domain1={some rows with same CL2-CL3} Domain2={some rows with another same CL2-Cl3} , ...

pleasecheck code below and give me idea what should i do? how to use strcmp() in this case? and how to show the target rows?

fid = fopen('Input2.txt','r')

data = textscan(fid,'%s %s %s %s')

fclose(fid)

indices = strcmp(data{2}{1},data{2})&&(data{1})

sum(indices)

Answer 1

[Matt Tearle]

Sounds like a job for categorical arrays! Huzzah! (Assuming you have Statistics Toolbox.) BTW, you said "dataset" but you're using cell arrays, so I assume you don't mean the dataset array in Stats TB. However, they may be a useful way to package your data. Anyway... why not make a new variable that is the combination of columns 2 and 3, and look for the unique values of that array:

twoandthree = nominal(strcat(data{2},'-',data{3}))
data = [data{:}];
domains = getlabels(twoandthree)
for k=1:length(domains)
    foo = data(twoandthree==domains{k},:)
end

If you don't have Stats TB, you can achieve the same result with unique and strcmp:

twoandthree = strcat(data{2},'-',data{3})
data = [data{:}];
domains = unique(twoandthree)
for k=1:length(domains)
    foo = data(strcmp(twoandthree,domains{k}),:)
end

Also, note I'm using [data{:}] to extract the four columns (each being a cell array) and concatenate them together into a single four-column table (ie a single n-by-4 cell array containing strings). If you're going to be accessing by rows, that's a nicer arrangement of data.

But, as I mentioned, dataset arrays may also make life nice, depending on what you're doing to do with the subsets.

data = dataset(data{:},'VarNames',strcat('cl',cellstr(num2str((1:4)'))))
twoandthree = nominal(strcat(data.cl2,'-',data.cl3))
domains = getlabels(twoandthree)
for k=1:length(domains)
    foo = data(twoandthree==domains{k},:)
end

[Bina]

you know what?????

YOU ARE MY HERO .... :D

[Matt Tearle]

[Strikes heroic pose] Don't thank me. Thank logical indexing. [Rides off into sunset]

[Walter Roberson]

Indexing! Indexing! Get your red-hot Logical Indexing here!

Authorized! Signed! Get your red-hot Logical Indexing!

Vectorized! Multidimensional! Endorsed by "Shane" Tearle!

Get your read-hot Logical Indexing!