How to assign value in an array depending on the index stated in another array

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want2know
want2know 2014-2-17
评论： Image Analyst 2014-2-17
Hi all,
After performing some processing, now the variable 'a' contains [2 5 9].
Let say i have another variable 'b', variable 'b' is pre-initialized to be zero depending on a length of input, let say 10. b = [0 0 0 0 0 0 0 0 0 0];
What I want is, the elements that are stated in variable 'a' should be set ONE in variable 'b'. b= [0 1 0 0 1 0 0 0 1 0]
How could I do this in Matlab? Appreciate any idea, thanks

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采纳的回答

Mischa Kim
Mischa Kim 2014-2-17
编辑：Mischa Kim 2014-2-17
Use
b(a) = 1
  1 个评论
want2know
want2know 2014-2-17
编辑：want2know 2014-2-17
Thanks so much... What is wrong if I got this error when using b(a)=1?
I did make sure variable 'a' contains only positive integers.
Subscript indices must either be real positive integers or logicals.

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更多回答（1 个）

Jos (10584)
Jos (10584) 2014-2-17
Welcome to the world of indexing!
Your problem:
a = [2 5 9]
b = [0 0 0 0 0 0 0 0 0 0];
b(a) = 1
Other interesting indexing things:
a = [1 3 7]
b = [0 0 0 ];
b(a) = 1 % automatic expansion of b
a = [2 2 2 2]
b = [0 0 0 0]
b(a) = 1 % no adding up ...
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want2know
want2know 2014-2-17
Thanks. I did make sure variable 'a' contains only positive integers.
'a' can only be positive integers, I confirm and have checked.
I have also added this line "a=round(a); b(a)=1;" still I got the same error...

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