MATLAB Answers

Chad Greene
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how to find elements in an array

Asked by Chad Greene
on 18 Feb 2014
Latest activity Commented on by Chad Greene
on 18 Feb 2014
Given this:
x = 1:100;
y = 201:300;
a = 250;
I know that
x(y==a)
will return 50, the value of x corresponding to the y index where y = a. Now if a has multiple elements, I'd like to find all the values of x corresponding to all the values of y where y equals any of the values in a. For example, if
a = [250; 215; 283];
I'd like to efficiently get the array [50; 15; 83]. How can I do this?

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2 Answers

Answer by Azzi Abdelmalek
on 18 Feb 2014
Edited by Azzi Abdelmalek
on 18 Feb 2014
 Accepted Answer

x = 1:100;
y = 201:300;
a = [250; 215; 283];
out=x(ismember(y,a))

  1 Comment

Brilliant, thank you!

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Answer by Thomas
on 18 Feb 2014
Edited by Thomas
on 18 Feb 2014

x = 1:100;
y = 201:300;
a=[ 215 250 283];
c=ismember(y,a)
x(c)
should give you
15 50 83

  1 Comment

thanks Thomas!

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