在 2022年9月1日星期四 UTC+2 18:34:36，<ery...@gmail.com> 写道： > On 9/1/22, James Tsai <james...@gmail.com> wrote: > > > > I find it very useful if I am allowed to define new local variables in a > > list comprehension. For example, I wish to have something like > > [(x, y) for x in range(10) for y := x ** 2 if x + y < 80], or > > [(x, y) for x in range(10) with y := x ** 2 if x + y < 80]. > > > > For now this functionality can be achieved by writing > > [(x, y) for x in range(10) for y in [x ** 2] if x + y < 80]. > You can assign a local variable in the `if` expression. For example: > > >>> [(x, y) for x in range(10) if x + (y := x**2) < 30] > [(0, 0), (1, 1), (2, 4), (3, 9), (4, 16)]
Yeah this works great but like [(x, y) for x in range(10) for y in [x**2]] I written before, is kind of a hack. And if initially I do not need an "if" condition in the list comprehension, this becomes less convenient. I still can write >>> [(x, y) for x in range(10) if (y := x**2) or True] But I wonder if Python could have a specific syntax to support this. -- https://mail.python.org/mailman/listinfo/python-list
