Find the index of the first integer of an array in another array

Question

Mike Mierlo van 2020-5-1

评论： dpb 2020-5-3

采纳的回答： dpb

Hi,

I want to find the index of the first integer of an array in another array. For example.

I have array A = [ 0 0 0 ] and I have array B= [ 1 2 3 4 0 0 0 5 6 7 0 0 8 9 ]

A = [ 0 0 0 ];
B= [ 1 2 3 4 0 0 0 5 6 7 0 0 8 9 ];

I want find the index of array B where array A starts. In this case array A starts from index 5 in array B.

So my outcome should be:

ans = 5

The thing I am looking for looks like find() but instead of finding just one value, I am searching for multiple values in succession of each other.

Answer 1

dpb 2020-5-1

Easier to find repeated patterns with string pattern searches than as vector arrays--

ix=strfind(sprintf('%d',ismember(B,A)),repmat('1',1,numel(A)));

Tommy 2020-5-1

Using strfind is brilliant! To expand on this, if A happens to contain different values:

ix=strfind(sprintf('%d',B),sprintf('%d',A));

dpb 2020-5-3

Actually that's a nice refinement -- no real need to convert to logical.