finding all instances in a vector

Hi all,

is there an easy way to find all instances of, say, numbers in vector x in a target vector, y?

For example, if I have a vector x which is: [ 1 4 10 ] how do i find all 1's 4's and 10's in y: [ 1 2 3 4 5 6 7 8 9 10 ]

sorry if this is a basic question.. i could write a for-loop of course, but i imagine there must be a more elegant way to do this. Thanks in advance!

[Liz]

sorry, i have to add one other thing.. it actually has to find all instances, even duplicates.. so it would be more like

x = [1 4 10] and y = [1 2 3 4 4 4 5 4 6 4 7 8 9 10]

[the cyclist]

No problem that this is a basic question! You asked it clearly and specifically, with an example of what you wanted. Good question.

Answer 1

[the cyclist]

You want the ismember() function.

[Liz]

thanks, that's useful.. but that doesn't give you the location of duplicates as well, does it?

[Liz]

oh! i get it now, you were right..

if i have

x = [1 4 10] and y = [1 2 3 4 4 4 5 4 6 4 7 8 9 10]

i can say: out = ismember(y,x) and i get:

out =

Columns 1 through 14

1 0 0 1 0 0 0 0 0 1 1 0 0 1

Columns 15 through 20

0 0 0 0 0 1

thank you!

[the cyclist]

Note that if you call ismember() with two outputs, then the first output indicates that the element was found, and the second output is an index to WHICH element of "x" it was.