finding an element that meet the conditions in a vector

Question

I have a vector that looks like this

A = [1 2 3 1 2 3 1 2 3]

and I would like to write a function that returns True if there is a number between 5 to 9 or False if not

The documentation for any should get you most of the way there — etmuse
– etmuse, Commented Aug 15, 2018 at 14:51

Paolo · Accepted Answer · 2018-08-15 15:03:50Z

2

As suggested by etmuse, you can just use any with two conditions.

function output = findelem(A) if(any(A>5 & A<9)) output = true; return; end output = false; end

Call function:

>>findelem([1 2 3 1 2 3 1 2 3]) returns logical 0 >>findelem([1 2 3 1 6 3 1 2 3]) returns logical 1

As @beaker correctly points out, you can simply use:

function output = findelem(A) output = (any(A>5 & A<9)) end

answered Aug 15, 2018 at 14:59

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4 Comments

any returns a boolean value. The if/else seems wasteful.

Yeah true, I added that in now, thanks. It was more for didactical purposes.

There was no else by the way :P

I realize that, but "if with return, otherwise falling through to a default assignment" was less concise.

Cris Luengo · Accepted Answer · 2018-08-15 15:40:46Z

An alternative solution uses ismember:

any(ismember(5:9,A))

It checks if any of the elements in 5:9 is present in A. If you leave out the any, it will tell you which of the elements is present in A:

>> ismember([1,5,9],A) ans = 1 0 0

(indicating that 1 is present, but 5 and 9 are not).