How to extract a value/s from a matrix that match with specific rows

Hi Friends,

I have a structure matrix (V= 1x6616 struc) as shown in the attched image. I want to sellect the all rows that match with the type '1' in the second colums. I have tried this code but it does not have any result.

for i = 1:numel(V)

C{1, i} = V{1,i}(strcmpi(V{1,i}.type,'1'),:);

end

%%I have tried this one as well, but no result.

C = V({'1'},{'latency','urevent','epoch'});

Answer 1

[Star Strider]

One possibility is to use the findgroups function to select the appropriate rows, then use that to index into the data.

type = string(randi(5, 10, 1));
others = rand(10,3);
Everything = [type, others]

Everything = 10×4 string array
    "5"    "0.15966"     "0.15112"    "0.40634" 
    "5"    "0.93737"     "0.24496"    "0.52959" 
    "1"    "0.28389"     "0.90393"    "0.84487" 
    "3"    "0.66454"     "0.51595"    "0.26782" 
    "1"    "0.89376"     "0.23557"    "0.56919" 
    "5"    "0.9502"      "0.53974"    "0.97958" 
    "4"    "0.98398"     "0.39381"    "0.054346"
    "1"    "0.65179"     "0.12865"    "0.53393" 
    "5"    "0.51813"     "0.6268"     "0.61095" 
    "2"    "0.055209"    "0.62481"    "0.98641" 

[G,ID] = findgroups(Everything(:,1))

G = 10×1

5 5 1 3 1 5 4 1 5 2

ID = 5×1 string array
    "1"
    "2"
    "3"
    "4"
    "5"

Result = Everything(G==1,:)

Result = 3×4 string array
    "1"    "0.28389"    "0.90393"    "0.84487"
    "1"    "0.89376"    "0.23557"    "0.56919"
    "1"    "0.65179"    "0.12865"    "0.53393"

In the absence of your data, I used the string function to create the first column. This turns ‘Everything’ into strings, however I am certain that this illustrates the concept.

.

[Abdulhakim]

Dear Star Strider,

Your code is amazing, but I needed to convert the data matrix into string first.

Thnaks

[Star Strider]

Thank you!

As always, my pleasure!

.