simplest way to build a series of numbers inside a for loop

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ddd ppp 2018-4-21

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评论： ddd ppp 2018-4-21

im trying to build a series of numbers inside a for loop. here is what i used to do this.

t=0
dt=.1
ii=0
for i=1:10
  % ii=[ii,i]    %method one
  t=[t,t(i)+dt]  %method 2   
end

is there a simpler method to do this?

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Answer 1

Ameer Hamza 2018-4-21

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You can simply use vector notation available in MATLAB as follow:

t = 0:0.1:1
ii = 0:10   % or ii = 0:1:10, if 2nd number is 1, it can be emitted.

The use of vector notation is also recommended because it is efficient and readable.

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Ameer Hamza 2018-4-21

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So what do you mean by the simplest way? If you still want to use for loop then you can make improvement by pre-allocating the memory for the array as follow:

t=zeros(1, 11); %create 1x11 array of zeros
dt=.1;
ii=zeros(1, 11);
for i=1:10
  ii(i+1) = i;    %method one
  t(i+1)= t(i)+dt;  %method 2   
end

This pre-allocation will show significant improvement in speed if t is a very large vector. Other than vectorization, it cannot get any simpler than this.

ddd ppp 2018-4-21