iterfield in MapNode can't be range (py3)

[djarecka]

Summary

In py3 range is not a list, and if iterfield in MapNode is defined as range than entire range is send to the interface at once.

Script/Workflow details

from nipype import Function, MapNode

def square_func(x):
    print(x, type(x))
    return x ** 2

square = Function(["x"], ["f_x"], square_func)

square_node = MapNode(square, name="square", iterfield=["x"])

square_node.inputs.x = range(4)
res  = square_node.run()

Actual behavior

print statement from square_func gives range(0, 4) <class 'range'>

Expected behavior

print statement from square_func should give 0 <class 'int'>, etc.

[satra]

@djarecka - in py3 range is a generator if you do list(range(4)) it should work fine.

[djarecka]

@satra - yes, I know, but my point was that it is misleading. MapNode doesn't give any warnings just sent the entire object to the function. It shouldn't be changed within the MapNode class?

[satra]

yes, it should result in an exception in this case, since it's not doing the correct thing.