How do I get an index like with ismember, but with values representing the number of occurances?

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Sebastian
Sebastian 2017-3-1
回答： Steven Lord 2017-3-1
I have some vectors, let's call them A and B, and I want to find all elements of A contained within B. So far I've gotten an logical index of all the unique elements, but I need to go one step further and count up repetitions as well. So for instance:
A = ['monday', 'tuesday', 'thursday', 'monday']
B = ['monday', 'tuesday', 'wednesday', 'thursday', 'friday', 'saturday', 'sunday']
Index = [2 1 0 1 0 0 0]

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采纳的回答

Stephen23
Stephen23 2017-3-1
编辑：Stephen23 2017-3-1
>> A = {'monday', 'tuesday', 'thursday', 'monday'};
>> B = {'monday', 'tuesday', 'wednesday', 'thursday', 'friday', 'saturday', 'sunday'};
>> idx = cellfun(@(s)nnz(strcmp(A,s)),B)
idx =
2 1 0 1 0 0 0

更多回答（1 个）

Steven Lord
Steven Lord 2017-3-1
A = {'monday', 'tuesday', 'thursday', 'monday'};
B = {'monday', 'tuesday', 'wednesday', 'thursday', 'friday', 'saturday', 'sunday'};
Ac = categorical(A, B);
Bc = categorical(B);
histcounts(Ac, Bc)
If your data is numeric you can skip the categorical steps, though you will need to add an extra element to the end of the second input. For categorical data, histcounts uses each category as a bin; for numeric data, it uses the second input as the edges of the bin. By default the leftmost edges are included in the bins. The extra element will be the rightmost edge of the last bin and will catch elements equal to the next to last element of the edges vector.
A = [1 2 4 1];
B = [1:7 Inf];
histcounts(A, B)

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