# To generate alternate 0's and 1's

16 views (last 30 days)
brijesh soni on 14 Aug 2019
Edited: Jos (10584) on 16 Aug 2019
Say I have A=[2 4 3 4 100 253 77 10 45]. I want to generate alternate 0's and 1' such that we have 2 zeros (i.e, zeros equal to size of 1st element), then 4 ones (ones equal to the size of 2nd element) and so on
Result should be : [0 0 1 1 1 1 0 0 0 1 1 1 1 . . . .]. How to do this?
Rik on 14 Aug 2019
I'm guessing RunLength should help out.

Andrei Bobrov on 14 Aug 2019
out = repelem(mod(0:numel(A)-1,2),A);
brijesh soni on 15 Aug 2019

dpb on 14 Aug 2019
One brute force way--
B=[];
for i=1:numel(A)
B=[B (1-mod(i,2))*ones(1,A(i))];
end

Jos (10584) on 14 Aug 2019
Edited: Jos (10584) on 16 Aug 2019
bitget(repelem(0:numel(A)-1, A), 1)
[update] I modified my original but erroneous answer bitget(repelem(1:numel(A), A), 2). In his comments below, Andrei hit a serious flaw in this one. One does need to look at the last bit!
Thanks Andrei, for pointing this out.
Jos (10584) on 16 Aug 2019
Sorry! You're complete right to look only at the last bit!

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