Pre allocation in matlab

v = [0 8 1 2 6 4 8]

How do I determine length of the vector?

Also, how do I pre-allocate the descending vector with all zeros?

Thank you!

Answer 1

[Walter Roberson]

length(v)

zeros(size(v))

[Seoyoung Cho]

thanks a lot!

[Seoyoung Cho]

do you know how to do pre-allocate the ascending vector with all zeros?

[Walter Roberson]

zeros(size(v)) works no matter whether you are planning to put ascending or descending variables; it also works even if you are planning to put complex numbers in (I mention those because complex numbers cannot generally be ordered into ascending or descending.)

Answer 2

[fred ssemwogerere]

leng=length(v); % length of a vector
pA=zeros(1,leng); % pre-allocation with zeros