"intersect" produces variable of class cast

In Matlab R2010a, version 7.10.0.499, I enter the following statements:

a = [10 20];
b = [30 10];
c = intersect (a,b);

and expect the result c = 10

But Matlab returns:

c = 

object of class 'cast' 

data description :   -not available-

data             :   10.00  

data unit        :   double

var description  :   -not available-

var              :   -not available-

var unit         :   -not available-

dVar             :   -empty-

sample frequency :   -empty-

leftCutOff       :   1

rightCutOff      :   1

What could be the reason, and how can I resolve this?

[Geoff Hayes]

Martin - perhaps you written a function called intersect that is overwriting the above. In the Command Window, type the following

 which -all intersect

to see which intersect functions you have.

Answer 1

[Steven Lord]

What does this command return?

 which -all cast

My guess is that you have an object named cast on your path and it is being used instead of the MATLAB function named CAST.

Given how frequently CAST is used in handling different types of data that are passed into functions (casting one of the inputs into the type of the other or casting both into a common type) I strongly recommend that you rename this class so that it doesn't conflict with the built-in function.

[Martin Schmid]

Thanks. This was indeed the culprit. I found a function named cast in a third-party toolbox. Removing this toolbox from the path solved the issue.

Answer 2

[Adam]

I suspect you must have your own function called 'intersect' that produces this behaviour

What is the result of typing

which intersect -all

?

It will likely produce quite a significant list, but it will show if you have your own function called intersect on your path that is hiding the builtin version.

When I run your code in R2015b I get exactly what you would expect - i.e. 10 as a 'double'

[Martin Schmid]

Thanks for your reply, but I don' think this is the case. Here is the result of "which intersect -all"

C:\Program Files\MATLAB\R2010a\toolbox\matlab\ops\intersect.m

C:\Program Files\MATLAB\R2010a\toolbox\matlab\ops\@cell\intersect.m % cell method

C:\Program Files\MATLAB\R2010a\toolbox\shared\statslib\@ordinal\intersect.m % ordinal method

C:\Program Files\MATLAB\R2010a\toolbox\shared\statslib\@nominal\intersect.m % nominal method

C:\Program Files\MATLAB\R2010a\toolbox\shared\statslib\@categorical\intersect.m % categorical method

[Adam]

Do you get the same answer if you remove everything from your path except the Matlab builtin and toolbox functions?

It is possible that while you haven't overwritten the intersect function you may have overwritten one of the functions that it itself calls.

Also, what is the result of

which cast -all

with your path as it is right now?