Find all occuarances of two numbers together

Hi,

I have an array, a = [ 0 -1 1 0 0 -1 1 0]

How can I fing all the ocurances of [ 1 0], ie. the index showing when the number 0 occurs after the number 1.

I want to create, b = [0 0 0 1 0 0 0 0 1].

I'm trying to use teh strfind fuction, but am stuck.

Thank you!

Inna

Answer 1

[Ameer Hamza]

Try this

a = [ 0 -1 1 0 0 -1 1 0];
idx = strfind(a, [1 0])+1;
b = zeros(size(a));
b(idx) = 1;

[Mathieu NOE]

yep ! it's exactly the same........:)

Answer 2

[Mathieu NOE]

hello Inna

you have to test a vs [1 0] and not [0 1]

this is the code :

a = [ 0 -1 1 0 0 -1 1 0];
t = [1 0];
ind = findstr(a,t); 
ind_zero = ind+1;  % findstr output index is for the first term of "t" (1) => to get the index of the trailing "0" you need to add 1
b = zeros(size(a));
b(ind_zero) = 1

[Bruno Luong]

Attention, better use strfind and not findstr, if a = 1

>> findstr(1,[0 1]) % not expected result

ans =

     2

>> strfind(1,[0 1])

ans =

     []

[Image Analyst]

findstr is not recommended. Use contains or strfind instead.