splitting matrix based on a value in one column
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Hi All,
I have a very large matrix part of which looks like this:
7 0
10 0
16 0
19 1
26 1
29 1
3 1
5 0
69 0
36 0
78 0
as you can see, the second column is either 0 or 1. I want to split this large matrix into sub matrices such that each sub matrix represent only the parts where the second column is 0. How do we do this? Thanks.
采纳的回答
Hard-coded indexing:
>> M = [7,0;10,0;16,0;19,1;26,1;29,1;3,1;5,0;69,0;36,0;78,0];
>> M(M(:,2)==0,:)
ans =
7 0
10 0
16 0
5 0
69 0
36 0
78 0
>> M(M(:,2)==1,:)
ans =
19 1
26 1
29 1
3 1
General solution:
>> [~,~,X] = unique(M(:,2));
>> C = accumarray(X,1:size(M,1),[],@(r){M(r,:)});
>> C{1}
ans =
7 0
10 0
16 0
36 0
69 0
78 0
5 0
>> C{2}
ans =
26 1
19 1
29 1
3 1
7 个评论
Thomas Booij
2018-6-16
Thanks a lot!
Aleem Akhtar
2018-9-30
That was great solution. You saved day for me.
Sandeep Karthikeyan
2019-8-7
Thanks a lot for the answer.
Chris Stillo
2020-12-15
Thank god someone knows what they are doing!
Pol Medir
2021-2-22
How would you do this if the sample of data was too large to input manually?
Stephen23
2021-2-22
@Pol Medir: import the data:
更多回答（1 个）
123456
2018-7-18
How could I do the same thing but divide cell array by strings from one row? Let's say, that the array looks like that:
t2 1 2
t2 2 3
t1 3 4
t2 4 5
t1 5 6
t1 6 7
I would like to recieve two arrays at the end:
1 2
2 3
4 5
and
3 4
5 6
6 7
1 个评论
Stephen23
2018-7-19
There are several solutions. One way is to input the first column into unique, and use its third output with my answer.
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