比较相同行的两个单元格阵列-MATLAB

Question

我有一个包含40,000行和400行的单元格字符串矩阵。我需要在first矩阵中找到适合second的那些行（行）。请注意，可能会有很多重复。

看起来：类似的40,000线路

Anna Frank  
Anna George  
Jane Peter  
Anna George  
Jane Peter    
etc.

这里我需要找到适合的

Anna George  
Jane Peter  

到目前为止，我发现的唯一方法是两个for函数和介于两者之间的一个if。但它相当慢：

for i=2:size(bigTable,1)
    for j = 1: size(smallTable,1)
        if sum(ismember(bigTable(i,1:2),smallTable(j,1:2))) == 2
            Total_R(size(Total_R,1)+1,1)= i;
        end
    end
end

Answer 1

我假设您的输入是这样设置的-

bigTable = 
    'Anna'    'Frank' 
    'Anna'    'George'
    'Jane'    'Peter' 
    'Anna'    'George'
    'Jane'    'Peter' 
smallTable = 
    'Anna'    'George'
    'Jane'    'Peter' 

为了解决你的问题，这里可以提出两种方法。

方法#1

基于ismember的方法

Total_R = find(sum(ismember(bigTable,smallTable,'rows'),2)==2)

方法#2

%// Assign unique labels to each cell for both small and big cell arrays, so that
%// later on you would be dealing with numeric arrays only and 
%// do not have to mess with cell arrays that were slowing you down
[unqbig,matches1,idx] = unique([bigTable(:) ; smallTable(:)])
big_labels = reshape(idx(1:numel(bigTable)),size(bigTable))
small_labels = reshape(idx(numel(bigTable)+1:end),size(smallTable))
%// Detect which rows from small_labels exactly match with those from big_labels
Total_R  = find(ismember(big_labels,small_labels,'rows'))

或者将最后一行的ismember替换为基于bsxfun的实现-

Total_R = find(any(all(bsxfun(@eq,big_labels,permute(small_labels,[3 2 1])),2),3))

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假设输入情况下这些方法的输出-

Total_R =
     2
     3
     4
     5