difference between 2 arrays

[Diez B. Roggisch]

Pierre wrote:

> Hello,
> 
> I would like to know how to find the difference (set operation)
> between 2 arrays :
> 
> a = array([1,2, 3,2,5,2])
> b = array([1,2])
> I want a - b = [3,5]
> 
> Well, the equivalence of setdiff in matlab...
> 
> I thought a.difference(b) could work, but no : AttributeError:
> 'numpy.ndarray' object has no attribute 'difference'

Not sure if this works with numpy-arrays, but

set(a) - set(b)

might just work if the arrays are iterable.

Diez