CODEWITHSUNDEEP
matlab
NikolaC
NikolaC

Reputation: 5

How to count number of consecutive ones in vector from the last position in Matlab

I want to count number of consecutive ones in a vector from last position in vector.

For example in a=[0 1 0 1 0 1] number of consecutive ones is 1.

In b = [1 0 0 1 1 1] number of consecutive ones is 3.

Upvotes: 2

Views: 145

Answers (2)

Dan
Dan

Reputation: 45741

Try this:

sum(a(find(diff(a),1,'last')+1:end))

or if you want to disregard the trailing 0s then

sum(a(find(diff(a)==1,1,'last')+1:end))

And if you want this to work when a contains only 1s then I would suggest

sum(a(find(diff([0,a])==1,1,'last'):end))

Upvotes: 1

Divakar
Divakar

Reputation: 221524

For a case, when you might have trailing zeros in the input -

find(A,1,'last') - find(diff(A)==1,1,'last')

Sample run -

>> A = [0,1,1,0,0,0,1,1,1,1,1,0,0]
A =
     0     1     1     0     0     0     1     1     1     1     1     0     0
>> find(A,1,'last') - find(diff(A)==1,1,'last')
ans =
     5

Upvotes: 2

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