lists and list item matches (ghost wodgame)

[nn]

On Sep 23, 10:56 am, nn <prueba... at latinmail.com> wrote:
> On Sep 22, 6:39 pm, Baba <raoul... at gmail.com> wrote:
>
>
>
> > On Sep 22, 9:18 pm, Baba <raoul... at gmail.com> wrote:
>
> > > On Sep 22, 3:38 pm, nn <prueba... at latinmail.com> wrote:
>
> > > > On Sep 21, 6:39 pm, Baba <raoul... at gmail.com> wrote:
>
> > > > > Hi
>
> > > > > query level: beginner
>
> > > > > as part of a learning exercise i have written code that:
>
> > > > > a) asks for a single letter input (assumption: only 1 letter wil be
> > > > > entered)
> > > > > b) adds that letter to list1 and then goes through list2 and checks:
>
> > > > >     1) if any item in list2 starts with list1 > if False: break
> > > > >     2) if list1 == any item in list2 > if True: break
>
> > > > > c) start again until 2) is True
>
> > > > > wordlist = ['hello', 'bye']
> > > > > handlist = []
> > > > > letter = raw_input('enter letter: ')
> > > > > handlist.append(letter)
> > > > > hand = "".join(handlist)
> > > > > for item in wordlist:
> > > > >     if item.startswith(hand):
> > > > >         while item.startswith(hand):
> > > > >             if hand not in wordlist:
> > > > >                 letter = raw_input('enter letter: ')
> > > > >                 handlist.append(letter)
> > > > >                 hand = "".join(handlist)
> > > > >             else: break
> > > > >         else: break
> > > > > print 'you loose'
>
> > > > > this code works but can it be optimised? i have the feeling that my
> > > > > nesting of IF, WHILE and FOR statements is overkill?
>
> > > > > inspired by part IV ofhttp://ocw.mit.edu/courses/electrical-engineering-and-computer-scienc...
>
> > > > > thanks
> > > > > Baba
>
> > > > Yes it is overkill. Especially the else:break from the while loop
> > > > makes it difficult to follow the logic. Also the program breaks down
> > > > if I use the following word list:
>
> > > > wordlist = ['hello', 'hamburger', 'bye']
>
> > > > enter letter: h
> > > > enter letter: a
> > > > you loose
>
> > > > I am not going to post any spoilers but I wrote your program using one
> > > > while loop and one generator expression for a total of 5 lines. My
> > > > version might be a bit too advanced but you should still be able to do
> > > > it using only one while, one for and one if instead.
>
> > > Hi nn,
>
> > > i wasn't expecting my code to fail with an additional word in it.
> > > While i was conscious that the whole construct was heavy i thought the
> > > reasoning worked. I keep looking at it but can't figure out the
> > > problem Can you give me a hint?
>
> > > In the meantime i found out that it is actually possible to populate a
> > > string (just like a list, a dictionary or a tuple). Here's what i've
> > > got now:
>
> > > wordlist = ['hello', 'bye']
> > > hand = ''
> > > for item in wordlist:
> > >     if item.startswith(hand):
> > >         while item.startswith(hand):
> > >             if hand not in wordlist:
> > >                 hand += raw_input('enter letter: ')
> > >                 print hand
> > >             else: break
> > >         else: break
> > > print 'you loose'
>
> > > But i can't figure out why it won't work when adding the extra word.
> > > Thanks by the way, it taught me not to be too confident when things
> > > SEEM to work...
>
> > > Why does it work when i use the built-in function any(iterable)?? To
> > > me using the any(iterable) function seems just like regrouping 3 lines
> > > into one...
>
> > > wordlist = ['hello','hamburger', 'bye', 'cello']
> > > hand = ''
> > > while any(item.startswith(hand) for item in wordlist):
> > >     if hand not in wordlist:
> > >         hand += raw_input('enter letter: ')
> > >     else: break
> > > print 'you loose'
>
> > > thanks
>
> > > Baba
>
> > Hi nn,
>
> > looking at my original code again i realise that having a raw_input
> > inside a FOR loop is flawed per se (at least for my purposes) so i
> > will just assume that i was taking the wrong approach initially. No
> > point in analysing it further. Thanks for your help.
>
> > Baba
>
> Since you seem to have figured it out I will post my version (python
> 3):
>
> wordlist = ['hello', 'hamburger', 'bye']
> inp=''
> while any(word.startswith(inp) and word!=inp for word in wordlist):
>     inp += input('enter letter: ')
> print('you lose')
>
> The reason why your original version didn't work was because each time
> you add a letter you have to go again over all words (in reality only
> a subset is required) and find a new one. Your version would find one
> word using the first letter and then exit.

Actually my version isn't right (for some values of right):

wordlist = ['hello', 'hamburger', 'bye']
inp=''
while any(word.startswith(inp) for word in wordlist) and (inp not in
wordlist):
    inp += input('enter letter: ')
print('you lose')

An explanation of how this changes the rules of the wordgame is left
as an exercise to the reader.