# Splitting a vector into vectors of different length

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Mojtaba on 16 Jul 2014
I want to split a vector with 90 arrays to 5 vectors with different lengths. The length of each vector is determined according to a normalized length like this: nl=[0.1642 .1516 .1259 .5583] Therefore the length of each vector is length=90*[0.1642 .1516 .1259 .5583]. But these lengths are not integer, and if i try to round this the length of will not equal to 90, it might be 89, 90, 91 or even 92 due to round of error.                        I would appreciate if anyone could assist me to write a code for this.
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Alfonso Nieto-Castanon on 17 Jul 2014
I am guessing you mean "a vector with 90 elements" instead of "a vector with 90 arrays"?

Alfonso Nieto-Castanon on 16 Jul 2014
Edited: Alfonso Nieto-Castanon on 17 Jul 2014
This is interesting, perhaps something like this would do (this implements a greedy correction of your initial estimate of the desired lengths of each segment until the segment lengths add-up to the proper value):
nl = [0.1642 .1516 .1259 .5583]; % normalized lengths of each segment
N = 90; % total length of data to segment
n = round(nl*N); % initial lengths of each segment
while sum(n)~=N % if lengths do not add-up to N
d = sign(N-sum(n)); % direction of change
[~,i] = min(abs(n+d-N*nl)); % best segment to modify
n(i) = n(i)+d; % change that segment length
end
Then you can simply split your original vector using mat2cell:
x = randn(1,90);
y = mat2cell(x, 1, n);