Random Choice is out of list range in Python?

Question

I am trying to create a program that will guess the number you entered. I was trying to get the computer to get the number in as few guesses as possible so I am doing something like a binary search. I keep getting a Index out of range when I run the code and it gets to total = total[the_low_one:computer2_guess]. I am confused why it is out of range. Should I be adding or subtracting one to the_low_one each time it hits a new low so it stays in range? I would appreciate any help as I am lost. Thanks a bunch in advance! Code:

def second_computer():
    global computer2_score
    computer2_score=0
    computer2_guess= -1
    the_low_one=1
    the_high_one=1000000
    total= range(1,1000000)
    while computer2_guess != pick_number:
        computer2_guess=random.choice(total)
        if computer2_guess>pick_number:
            total=total[the_low_one:computer2_guess]
            the_high_one=computer2_guess-1
        else:
            total=total[computer2_guess:the_high_one]
            the_low_one=computer2_guess+1
        computer2_score+=1

Your formatting needs a bit work -- but I think your problem is you initialize `the_low_one` to 1 instead of 0. — user590028, Dec 24 '14 at 00:50
Your indentation after the `while` statement needs to be fixed — dazedconfused, Dec 24 '14 at 00:54
Oh, sorry I didn't realize it didn't indent properly online. Thanks for noticing! I tried changing it to 0 but the same error happened. — user3818089, Dec 24 '14 at 00:55
You have a number of logic errors. Your slices are using values from the total[] array, rather than indicies. And where is pick_number defined? — user590028, Dec 24 '14 at 01:00
I'm curious -- why did you not use a simple binary search? http://stackoverflow.com/questions/212358/binary-search-in-python — user590028, Dec 24 '14 at 01:02
I can't really figure out how to set it up and make it work. I think my program would work fine if I could figure out how to get rid of the Index Error. — user3818089, Dec 24 '14 at 01:06

score 1 · Accepted Answer · answered Dec 24 '14 at 01:07

1

As total shrinks, the numerical values in the list no longer line up with their indices. You could make it work by doing

total=total[total.index(the_low_one):total.index(the_high_one)]

A simpler approach would be to do away with total altogether and set computer2_guess=random.randint(the_low_one,the_high_one)

answered Dec 24 '14 at 01:07

Gall

38
4

I don't know why I didn't just do the `randint`in the first place. Thanks! – user3818089 Dec 24 '14 at 01:13
1

what happens if randint is 1000000? – Padraic Cunningham Dec 24 '14 at 01:37

Random Choice is out of list range in Python?

1 Answers1