[Tutor] Indexing a list with nested tuples

[bob gailer]

On 8/2/2011 10:44 PM, Alexander Quest wrote:
> Hi guys- I'm having a problem with a list that has nested tuples:
>
> attributes = [("strength", 0), ("health  ", 0), ("wisdom  ", 0), 
> ("dexterity", 0)]
>
> I've defined the list above with 4 items, each starting with a value 
> of 0. The player
> enters how many points he or she wants to add to a given item. The 
> selection menu
> is 1 - strength; 2 - health; 3 - wisdom; 4- dexterity. So the 
> "selection" variable is actually
> 1 more than the index location of the intended item. So I have the 
> following code:
>
> print("Added ", points, "to ", attributes[selection-1][0], "attribute.")
>
> My intent with this is to say that I've added this many points 
> (however many) to the
> corresponding item in the list. So if the player selects "1", then 
> selection = 1, but I subtract
> 1 from that (selection -1) to get the index value of that item in the 
> list (in this case 0). Then I
> have [0] to indicate that I want to go to the second value within that 
> first item, which is the
> point value. I get an error saying that list indices must be integers, 
> not strings. I get a similar
> error even if I just put attributes[selection][0] without the minus 1.
>
> Also, it seems that the tuple within the list cannot be modified 
> directly, so I can't add points to the original value of "0" that all 
> 4 items start with. Is there a way to keep this nested list with
> tuples but be able to modify the point count for each item, or will it 
> be better to create a dictionary or 2 separate lists (1 for the names 
> "Strength, Health, Wisdom, Dexterity" and one
> for their starting values "0,0,0,0")? Any suggestions/help will be 
> greatly appreciated!!!
Thanks for inquiring. Some guidelines about questions:

1 - show us more code. in this case specifically how you obtain user input.
2 - show the complete traceback

What does the error message tell you? Why would selection be a string 
rather than an integer? This has to do with how you obtain selection 
from the user. What

Why did you expect to be able to alter the value of a tuple element? 
Tuples are immutable! Use a list instead.

HTH

-- 
Bob Gailer
919-636-4239
Chapel Hill NC