[Tutor] swapping list elements based on some criterion

[Emad Nawfal (عمـ نوفل ـاد)]

On Sat, Oct 8, 2011 at 12:11 PM, Andreas Perstinger <
andreas.perstinger at gmx.net> wrote:

> On 2011-10-08 09:53, Peter Otten wrote:
>
>> Emad Nawfal (عمـ نوفل ـاد) wrote:
>>
>>>  Here is the function as I used it, and it works fine:
>>>
>>>  def swap(sentence):
>>>    buffer = []
>>>    adjectives = []
>>>    for word in sentence.split():
>>>        if word.endswith('/ADJ'):
>>>            adjectives.append(word)
>>>        elif word.endswith('/N'):
>>>            buffer.append(word)
>>>            buffer.extend(adjectives)
>>>
>>>            adjectives = []
>>>        else:
>>>            buffer.append(word)
>>>    return ' '.join(buffer)
>>>
>>
>> Does the classification scheme allow for adjectives that are not followed
>> by
>> a noun? Example: if "good" in the sentence "That looks good" were
>> classified
>> as an adjective it would be silently dropped.
>>
>
> As far as I know, adjectives are always in front of a noun in English.
> Therefore I suggest iterating backwards and everytime you come across a noun
> check if it is preceded by an adjective and swap the positions. Iterating
> backwards is necessary for cases where more than one adjective is in front
> of the noun. So the noun "floats" towards the beginning of the sentence
> while all adjectives without nouns (or behind nouns - I don't know if that's
> possible in English) will stay where they are:
>
> def swap(sentence):
>    s = sentence.split()
>    for i in reversed(range(len(s))):
>        if s[i].endswith("/N") and s[i-1].endswith("/ADJ"):
>            s[i], s[i-1] = s[i-1], s[i]
>    return s
>
> >>> swap("the/DET tall/ADJ man/N plays/VBZ well/ADV")
> ['the/DET', 'man/N', 'tall/ADJ', 'plays/VBZ', 'well/ADV']
>
> >>> swap("That/DET looks/VBZ good/ADJ")
> ['That/DET', 'looks/VBZ', 'good/ADJ']
>
> >>> swap("He/P is/VBZ a/ART big/ADJ old/ADJ man/N who/P went/VBZ
> crazy/ADJ")
> ['He/P', 'is/VBZ', 'a/ART', 'man/N', 'big/ADJ', 'old/ADJ', 'who/P',
> 'went/VBZ', 'crazy/ADJ']
>
> Bye, Andreas
>
>
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Thanks Andreas and Peter. Andreas's solution works perfect for me as it
takes care of non-qualitative adjectives.
I now have enough information to get started on my little project. Hope you
don't mind my coming back to you if something comes up.
-- 
لا أعرف مظلوما تواطأ الناس علي هضمه ولا زهدوا في إنصافه كالحقيقة.....محمد
الغزالي
"No victim has ever been more repressed and alienated than the truth"

Emad Soliman Nawfal
Indiana University, Bloomington
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