bump!
On Wed, Jan 13, 2021 at 9:32 AM Peter O'Connor <peter.ed.ocon...@gmail.com>
wrote:
> I often find that python lacks a nice way to say "only pass an argument
> under this condition". (See previous python-list email in "Idea: Deferred
> Default Arguments?")
>
> Example 1: Defining a list with conditional elements
> include_bd = True
> current_way = ['a'] + (['b'] if include_bd else [])+['c']+(['d'] if
> include_bd else [])
> new_way = ['a', 'b' if include_bd, 'c', 'd' if include_bd]
> also_new_way = list('a', 'b' if include_bd, 'c', 'd' if include_bd)
>
> Example 2: Deferring to defaults of called functions
> def is_close(a, b, precicion=1e-9):
> return abs(a-b) < precision
>
> def approach(pose, target, step=0.1, precision=None):
> # Defers to default precision if not otherwise specified:
> velocity = step*(target-pose) \
> if not is_close(pose, target, precision if precision is not
> None) \
> else 0
> return velocity
>
> Not sure if this has been discussed, but I cannot see any clear downside
> to adding this, and it has some clear benefits (duplicated default
> arguments and **kwargs are the scourge of many real world code-bases)
>
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