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Groups > comp.lang.python > #49571

Re: Stupid ways to spell simple code

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On 1 July 2013 14:14, Chris Angelico <rosuav@gmail.com> wrote:
> On Mon, Jul 1, 2013 at 10:59 PM, Neil Cerutti <neilc@norwich.edu> wrote:
>> On 2013-06-30, Chris Angelico <rosuav@gmail.com> wrote:
>>> So, here's a challenge: Come up with something really simple,
>>> and write an insanely complicated - yet perfectly valid - way
>>> to achieve the same thing. Bonus points for horribly abusing
>>> Python's clean syntax in the process.
>>>
>>> Go on, do your worst!
>>
>> I've often thought it was redundant for Python to support 'if'
>> when it has dictionaries, cf the rationale for having no
>> 'switch'.
>>
>> valid_name = None
>> while not valid_name:
>>     name = input("Enter your name: ")
>>     valid_name = {
>>         True: lambda: print("No name longer than 20 letters."),
>>         False: lambda: True,
>>     }[len(name) > 20]()
>>
>> Much better.
>
> Good! Good! But, waaaah. Waaaah.
>
> def get_name():
>   while True:
>     name = input("Enter your name: ")
>     yield {
>         True: lambda: print("No name longer than 20 letters."),
>         False: lambda: name,
>     }[len(name) > 20]()
> name = next(filter(None,get_name()))

Oh, cruel. But you can do worse. Who needs "while" when you have
filter(iter(FUNCTION, object()))?

def get_name():
    name = input("Enter your name: ")
    return [
        lambda: name,
        lambda: print("No name longer than 20 letters."),
    ][len(name) > 20]()

name = next(filter(None, iter(get_name, object())))


But who needs *any* of this! Defining functions is so old-hat. It's
all already in the standard library (using only assignments and function-calls):

from functools import partial
from operator import getitem, ge, methodcaller
from itertools import compress, tee
apply = methodcaller("__call__")
ret_true = partial(getitem, [True], 0)
print_invalid = partial(print, "No name longer than 20 letters.")
inputs = iter(partial(input, "Enter your name: "), ...)
inputs, valid = tee(inputs)
valid = map(len, valid)
valid = map(partial(ge, 20), valid)
side_effect_valid = map(partial(getitem, [print_invalid, ret_true]), valid)
side_effect_valid = map(apply, side_effect_valid)
valid_inputs = compress(inputs, side_effect_valid)
name = next(valid_inputs)


Which can be "neatly" expressed as two statements (I'm struggling to
got it to one without those evil lambdas):

from functools import partial
from operator import getitem, ge, methodcaller
from itertools import compress, tee

inputs, valid = tee(iter(partial(input, "Enter your name: "), ...))

name = next(
    compress(
        inputs,
        map(
            methodcaller("__call__"),
            map(
                partial(
                    getitem,
                    [
                        partial(print, "No name longer than 20 letters."),
                        partial(getitem, [True], 0)
                    ]
                ),
                map(
                    partial(ge, 20),
                    map(len, valid)
                )
            )
        )
    )
)


Beautiful, see?


Of course, the most powerful function deals with this much more quickly:

exec("""
while True:
    name = input("Enter your name: ")

    if len(name) <= 20:
        break

    else:
        print("No name longer than 20 letters.")
""")

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Thread

Stupid ways to spell simple code Chris Angelico <rosuav@gmail.com> - 2013-06-30 16:06 +1000
  Re: Stupid ways to spell simple code Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-30 07:58 -0700
    Re: Stupid ways to spell simple code Joshua Landau <joshua.landau.ws@gmail.com> - 2013-06-30 16:08 +0100
    Re: Stupid ways to spell simple code Chris Angelico <rosuav@gmail.com> - 2013-07-01 01:20 +1000
    Re: Stupid ways to spell simple code Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-30 11:26 -0600
  Re: Stupid ways to spell simple code Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-30 17:36 +0000
    Re: Stupid ways to spell simple code Roy Smith <roy@panix.com> - 2013-06-30 13:44 -0400
    Re: Stupid ways to spell simple code Joshua Landau <joshua.landau.ws@gmail.com> - 2013-06-30 22:52 +0100
  Re: Stupid ways to spell simple code Neil Cerutti <neilc@norwich.edu> - 2013-07-01 12:59 +0000
    Re: Stupid ways to spell simple code Chris Angelico <rosuav@gmail.com> - 2013-07-01 23:14 +1000
    Re: Stupid ways to spell simple code Joshua Landau <joshua.landau.ws@gmail.com> - 2013-07-01 17:30 +0100
    Re: Stupid ways to spell simple code Marcin Szamotulski <mszamot@gmail.com> - 2013-07-01 20:36 +0100
      Re: Stupid ways to spell simple code Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-07-01 22:09 +0000
        Re: Stupid ways to spell simple code 88888 Dihedral <dihedral88888@gmail.com> - 2013-07-01 21:16 -0700
        Re: Stupid ways to spell simple code Marcin Szamotulski <mszamot@gmail.com> - 2013-07-02 07:22 +0100
    Re: Stupid ways to spell simple code Chris Angelico <rosuav@gmail.com> - 2013-07-02 02:32 +1000
  Re: Stupid ways to spell simple code Russel Walker <russ.pobox@gmail.com> - 2013-07-02 00:33 -0700

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