Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #99949

Re: filter a list of strings

Show all headers | View raw

In a message of Thu, 03 Dec 2015 10:27:19 +0100, c.buhtz@posteo.jp writes:
>Thank you for your suggestion. This will help a lot.
>
>On 2015-12-03 08:32 Jussi Piitulainen <harvesting@is.invalid> wrote:
>> list = [ item for item in list
>>          if ( 'Banana' not in item and
>>               'Car' not in item ) ]
>
>I often saw constructions like this
>  x for x in y if ...
>But I don't understand that combination of the Python keywords (for,
>in, if) I allready know. It is to complex to imagine what there really
>happen.
>
>I understand this
>  for x in y:
>    if ...
>
>But what is about the 'x' in front of all that?

This is a list comprehension.
see: https://docs.python.org/2/tutorial/datastructures.html#list-comprehensions

But I would solve your problem like this:

things_I_do_not_want = ['Car', 'Banana', <add all of them here>]
things_I_want = []

for item in list_of_everything_I_started_with:
    if item not in things_I_do_not_want:
       things_I_want.append(item)

Laura

Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

filter a list of strings <c.buhtz@posteo.jp> - 2015-12-03 02:15 +0100
  Re: filter a list of strings Jussi Piitulainen <harvesting@is.invalid> - 2015-12-03 08:32 +0200
    Re: filter a list of strings <c.buhtz@posteo.jp> - 2015-12-03 10:27 +0100
      Re: filter a list of strings Jussi Piitulainen <harvesting@is.invalid> - 2015-12-03 13:53 +0200
      Re: filter a list of strings Peter Pearson <pkpearson@nowhere.invalid> - 2015-12-05 19:42 +0000
    Re: filter a list of strings Chris Angelico <rosuav@gmail.com> - 2015-12-03 20:40 +1100
    Re: filter a list of strings Wolfgang Maier <wolfgang.maier@biologie.uni-freiburg.de> - 2015-12-03 10:46 +0100
    Re: filter a list of strings Laura Creighton <lac@openend.se> - 2015-12-03 10:53 +0100
    Re: filter a list of strings jmp <jeanmichel@sequans.com> - 2015-12-03 11:03 +0100
    Re: filter a list of strings Peter Otten <__peter__@web.de> - 2015-12-03 11:13 +0100
    Re: filter a list of strings Denis McMahon <denismfmcmahon@gmail.com> - 2015-12-03 14:16 +0000
      Re: filter a list of strings Jussi Piitulainen <harvesting@is.invalid> - 2015-12-03 17:02 +0200
  Re: filter a list of strings Grobu <snailcoder@retrosite.invalid> - 2015-12-03 13:17 +0100

csiph-web