How can I convert indices into a binary matrix?

Question

MByk 2024-2-18

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2083388-how-can-i-convert-indices-into-a-binary-matrix

评论： Alexander 2024-2-18

Test.txt

Hello all, I have a txt file that includes list of selected items (there are 10 items in total). I am reading the file using "readmatrix". I want to create a binary (logical) matrix as in the example below but I am getting "The subscript vectors must all be of the same size." message. How can I fix it? Thanks for the help.

1,3,5     -> 1,0,1,0,1,0,0,0,0,0
1,2,3,7   -> 1,1,1,0,0,0,1,0,0,0
1,2,6,7,8 -> 1,1,0,0,0,1,1,1,0,0
1,2,3     -> 1,1,1,0,0,0,0,0,0,0
...

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Stephen23 2024-2-18

@MByk: please upload a sample data file by clicking the paperclip button.

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Answer 1

Dyuman Joshi 2024-2-18

2
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2083388-how-can-i-convert-indices-into-a-binary-matrix#answer_1411078

编辑：Dyuman Joshi 2024-2-18

在 MATLAB Online 中打开

Test.txt

ItemSet = readmatrix('Test.txt','NumHeaderLines',0)
ItemSet = 31×7
     1     5     9    10   NaN   NaN   NaN
     1     5     9    10   NaN   NaN   NaN
     1     5     8     9    10   NaN   NaN
     1     5     7     9    10   NaN   NaN
     3     5     9    10   NaN   NaN   NaN
     3     5     8     9    10   NaN   NaN
     3     5     7     9    10   NaN   NaN
     3     4     5     9    10   NaN   NaN
     3     4     5     8     9    10   NaN
     3     4     5     7     9    10   NaN
tic
s = size(ItemSet);
%corresponding row values
row = repelem((1:s(1)).', 1, s(2))
row = 31×7
     1     1     1     1     1     1     1
     2     2     2     2     2     2     2
     3     3     3     3     3     3     3
     4     4     4     4     4     4     4
     5     5     5     5     5     5     5
     6     6     6     6     6     6     6
     7     7     7     7     7     7     7
     8     8     8     8     8     8     8
     9     9     9     9     9     9     9
    10    10    10    10    10    10    10
%maximum value
m = max(ItemSet, [], 'all');
%subscript values
idx = [row(:) ItemSet(:)];
%check for NaN values
k = isnan(idx(:,2));
out = accumarray(idx(~k,:), 1, [s(1) m])
out = 31×10
     1     0     0     0     1     0     0     0     1     1
     1     0     0     0     1     0     0     0     1     1
     1     0     0     0     1     0     0     1     1     1
     1     0     0     0     1     0     1     0     1     1
     0     0     1     0     1     0     0     0     1     1
     0     0     1     0     1     0     0     1     1     1
     0     0     1     0     1     0     1     0     1     1
     0     0     1     1     1     0     0     0     1     1
     0     0     1     1     1     0     0     1     1     1
     0     0     1     1     1     0     1     0     1     1
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