Group items tagged

Last week we looked at the itertools module and how its iterator based functions can be faster than doing things from scratch. One of the examples showed a function using itertools.takewhile to be much faster than one using itertools.groupby. Some feedback we got, asked, what then is the point of groupby if it's just a slower version of other functionality?

6.5.1 Itertool functions The following module functions all construct and return iterators. Some provide streams of infinite length, so they should only be accessed by functions or loops that truncate the stream.