Creating a Null list, seems to create a null tuple instead

[JimDibb]

Please don't critique my algorithm as I'm a rank newbie (or go ahead, I can take it :) ). But I can't figure the following out.

def shuffle():
    """ Return a list of indices from 0-51 with no repeats."""
    index = range (0,52)
    shuffled_list = list()   # or shuffled_list = [] does the same
    while index:
        card = random.choice(index)
        index.remove(card)
        shuffled_list.append(card)
#        print shuffled_list
    return shuffled_list
 

shuffled_list always seems to be defined as () when I look in the debugger, so I continually get

File "C:\Python25\cards.py", line 29, in shuffle
while index:
AttributeError: 'tuple' object has no attribute 'append'

I have no idea whats wrong here.

[Prasannaa]

Hi
I am also new to python.
I tried your code, it works fine for me.
(I use Python 2.5).

Regards,
Prasannaa

[JimDibb]

Hi
I am also new to python.
I tried your code, it works fine for me.
(I use Python 2.5).

Regards,
Prasannaa

Well, interestingly, I exited Winpython, restarted it and it works for me too now. I fixed one problem in preceeding code at the same time. My C background had intruded and I had

deck = [];
 

Does anyone know what that causes? I got no errors but perhaps it messed something up in the intepreter and it couldn't recover?

Thanks!

[bvdet]

Well, interestingly, I exited Winpython, restarted it and it works for me too now. I fixed one problem in preceeding code at the same time. My C background had intruded and I had

deck = [];
 

Does anyone know what that causes? I got no errors but perhaps it messed something up in the intepreter and it couldn't recover?

Thanks!

Since 'list()' returns '[]', I cannot explain why you had the tuple problem. Your algorithm looks fine. For the record, the random module has other functions that do basically the same thing:

>>> deck = range(0,52)
>>> random.shuffle(deck)
>>> deck
[41, 10, 23, 46, 14, 25, 5, 37, 9, 11, 3, 47, 1, 49, 22, 20, 29, 15, 51, 8, 4, 18, 17, 26, 36, 43, 34, 0, 48, 2, 50, 6, 16, 33, 28, 24, 38, 44, 35, 27, 42, 31, 7, 45, 40, 12, 13, 21, 19, 39, 32, 30]
>>> 

OR

>>> random.sample(range(0,52), 52)
[10, 26, 7, 45, 46, 48, 16, 1, 34, 32, 6, 35, 30, 18, 0, 21, 49, 8, 40, 29, 4, 36, 11, 15, 42, 28, 5, 3, 25, 27, 20, 9, 43, 17, 24, 39, 22, 33, 38, 2, 47, 51, 50, 13, 12, 44, 19, 31, 37, 14, 41, 23]
>>> 

[JimDibb]

Since 'list()' returns '[]', I cannot explain why you had the tuple problem. Your algorithm looks fine. For the record, the random module has other functions that do basically the same thing:

>>> deck = range(0,52)
>>> random.shuffle(deck)
>>> deck
[41, 10, 23, 46, 14, 25, 5, 37, 9, 11, 3, 47, 1, 49, 22, 20, 29, 15, 51, 8, 4, 18, 17, 26, 36, 43, 34, 0, 48, 2, 50, 6, 16, 33, 28, 24, 38, 44, 35, 27, 42, 31, 7, 45, 40, 12, 13, 21, 19, 39, 32, 30]
>>> 

OR

>>> random.sample(range(0,52), 52)
[10, 26, 7, 45, 46, 48, 16, 1, 34, 32, 6, 35, 30, 18, 0, 21, 49, 8, 40, 29, 4, 36, 11, 15, 42, 28, 5, 3, 25, 27, 20, 9, 43, 17, 24, 39, 22, 33, 38, 2, 47, 51, 50, 13, 12, 44, 19, 31, 37, 14, 41, 23]
>>> 

EXCELLENT, thanks!

[bartonc]

Well, interestingly, I exited Winpython, restarted it and it works for me too now.

I've heard of this type of old vs new namespace problem in PythonWin (never experienced it since I only used that IDE for a day or two). There are issues with import vs reload (I never use those either) IDLE's Run Module has always worked for me. Perhaps you weren't using PythonWin's Run command???

I fixed one problem in preceeding code at the same time. My C background had intruded and I had

deck = [];
 

Does anyone know what that causes? I got no errors but perhaps it messed something up in the intepreter and it couldn't recover?

Thanks!

Python will create an empty list. But then, if you

deck = 'abc'

(or something) Python simply re-assigns the name to the new object and if that was the only reference to the empty list, it is marked for Garbage Collection.