Why is my index [4] out of range when there are 4 items in my list?-CodePudding

my error:

if player_order_chooser[4] == player_a: IndexError: list index out of range

>import random
> 
>player_a = "Joe" 
>player_b = "john" 
>player_c = "Donald" 
>player_d = "Brady"
> 
> 
>player_order_chooser = [player_a,player_b,player_c,player_d]
>random.shuffle(player_order_chooser) 
>x = len(player_order_chooser)
>print(x)
>print(player_order_chooser[1]) 
>print(player_order_chooser[2])
>print(player_order_chooser[3]) 
>print(player_order_chooser[4])

CodePudding user response：

The index of array/list starts from 0 instead of 1.

If you have array of length 4, that's mean it has values stored in indexes from 0 to 3.

In your example, without using:

random.shuffle(player_order_chooser)

In order to print "Joe" which is stored in string player_a:

>print(player_order_chooser[0])

While, in order to print "Brady" which is stored in string player_d:

>print(player_order_chooser[3])

After using random.shuffle() the results will change but the size of index remains the same.

CodePudding user response：

The index start at 0, just look at the prints and you will notice the problem:

4
john
Brady
Donald
Traceback (most recent call last):
  File "test.py", line 16, in <module>
    print(player_order_chooser[4])
IndexError: list index out of range

The first name printed is the second that you setted.

Change your code to:

import random

player_a = "Joe" 
player_b = "john" 
player_c = "Donald" 
player_d = "Brady"
 

player_order_chooser = [player_a,player_b,player_c,player_d]
random.shuffle(player_order_chooser) 
x = len(player_order_chooser)
print(x)
print(player_order_chooser[0]) 
print(player_order_chooser[1])
print(player_order_chooser[2]) 
print(player_order_chooser[3])