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| From | Terry Reedy <tjreedy@udel.edu> |
| Subject | Re: learning to use iterators |
| Date | Tue, 23 Dec 2014 15:46:27 -0500 |
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On 12/23/2014 1:55 PM, Seb wrote: >>>> def n_grams(a, n): > ... z = (islice(a, i, None) for i in range(n)) > ... return zip(*z) > I'm impressed at how succinctly this islice helps to build a list of > tuples with indices for all the required windows. However, I'm not > quite following what goes on in the first line of the function. > Particulary, what do the parentheses do there? The parenthesized expression is a generator expression. The ()s are part of the syntax and may only be omitted when the expression is the argument of a function call, as in >>> list((i for i in range(0, 7, 2))) [0, 2, 4, 6] >>> list(i for i in range(0, 7, 2)) [0, 2, 4, 6] -- Terry Jan Reedy
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Re: learning to use iterators Terry Reedy <tjreedy@udel.edu> - 2014-12-23 15:46 -0500
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