how to search a value of a matrix and replace by vector value?

Question

Mirbahar Naadiya 2017-11-9

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/366164-how-to-search-a-value-of-a-matrix-and-replace-by-vector-value

评论： Mirbahar Naadiya 2017-11-10

hello everyone, it would be very kind of you if someone could help me to figure it out. i want to replace elements of matrix, the matrix contains student IDs.

if true
  % code
User1   User2
84599  84607
151791  152219
151791  152195
357518  357809
357518  357863
end

the total number of users in the mentioned data is 8, one users may have many records in data.

 if true
    % code
84599  1
84607  2
151791  3
152195  4
152219  5
357518  6
357809  7
357863  8
end
I want to find one value like "84599" in all data and replace it by "1", then "84607" replace it by "2". The below result is the desired one
if true
  % code
1  2
3  4
5  6
7  8
6  8
end
 Thanks in advance

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Rik 2017-11-9

The naive approach would be a for-loop, but if you take a look at ismember, you might be able to find a method of doing in one go with clever indexing.

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Answer 1

Eric 2017-11-9

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/366164-how-to-search-a-value-of-a-matrix-and-replace-by-vector-value#answer_290287

在 MATLAB Online 中打开

 studentIDs = [84599 84607; ...
     151791 152219; ...
     151791 152195; ...
     357518 357809; ...
     357518 357863];
 ID2code = [84599 1; ...
      84607 2; ...
     151791 3; ...
     152195 4; ...
     152219 5; ...
     357518 6; ...
     357809 7; ...
     357863 8];
 output = studentIDs;
 for i=1:size(ID2code,1)
     output(studentIDs==ID2code(i,1)) = ID2code(i,2);
 end