On Tue, Oct 05, 2021 at 08:45:55AM +0100, Alex Waygood wrote:
> I think there definitely should be a more obvious way to do this
> (specifically the first and last keys/values/items of a dictionary
What's your use-case for caring what the first and last key in a dict
is?
> An anti-pattern you see quite often on Stack Overflow to
> get the first key of a dictionary is something like the following:
>
> first_key = list(mydict.keys())[0]
Example number 9758 of why not to trust everything you see on
Stackoverflow :-)
> Another possibility I've been wondering about was whether several
> methods should be added to the dict interface:
>
> dict.first_key = lambda self: next(iter(self))
> dict.first_val = lambda self: next(iter(self.values()))
> dict.first_item = lambda self: next(iter(self.items()))
> dict.last_key = lambda self: next(reversed(self))
> dict.last_val = lambda self: next(reversed(self.values()))
> dict.last_item = lambda self: next(reversed(self.items()))
Not every *one* line function needs to be a builtin.
> But I think I like a lot more the idea of adding general ways of doing
> these things to itertools.
How about some recipes? `next(iter(mydict))` etc is a simple, easy,
memorable, readable, maintainable way to get what you want. Composition
of simple operations is great! Not everything needs to be a named
function:
def addone(x):
"""Return x + 1.
>>> addone(32)
33
"""
return x + 1
--
Steve
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