通过与另一个数组比较在数组中查找元素 [英] finding an element in an array by comparing it with another array

问题描述

我有一个矩阵

a = [ 1 'cancer'
      2 'cancer'
      3 'cancer'
      4 'noncancer'
      5 'noncancer' ]

我还有另一个值矩阵

b = [ 4
      5
      2 ]

现在我必须将b矩阵值与a的值进行比较，并且输出应为

Now I have to compare the b matrix values with values of a and the output should be

output = [ 4  'noncancer'
           5  'noncancer'
           2  'cancer']

如何在matlab中做到这一点?

How can I do this in matlab ?

推荐答案

您可以使用

You can use ismember:

a = { 1 'cancer'
      2 'cancer'
      3 'cancer'
      4 'noncancer'
      5 'noncancer' };

  b = [ 4
      5
      2 ];

 a(ismember([a{:,1}], b),:)

这导致

ans = 

    [2]    'cancer'   
    [4]    'noncancer'
    [5]    'noncancer'

要以b指定的顺序显示结果，请使用(按照后续问题的要求:

To display the results in the order specified by b use (as requested in a follow-up question: In the same order, finding an element in an array by comparing it with another array)

[logicIDX, numIDX]  = ismember(b, [a{:,1}]);
a(numIDX, :)

结果是:

ans = 

   [4]    'noncancer'
   [5]    'noncancer'
   [2]    'cancer' 

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