difference between range in py3 and xrange in py2

[Skaperen]

xrange in python2 is just a generator. In python3, it's a special class that normally acts like a generator, but also supports slicing/indexing/min/max/len, using math to calculate what those values would be (instead of exhausting the range), so it's still very fast.

but in a straight assignment to a variable, they can operate differently giving surprises because you are getting something different. that's not how Python3 was promoted.