While loop: list index out of range

Question

I've been making a function to search through two lists and check if a character is in both lists.The error

"IndexError: list index out of range"

keeps coming up. I put this through python Tutor and it seems like the while loop is totally ignored.I'm coding this search without using the in function in an if statement. Any help would be much appreciated!

Here is my code:

aList = ["B" , "S" , "N" , "O" , "E" , "U" , "T" ]
userInput = "TOE"
userInputList = list(userInput)
letterExists = 0

while (letterExists < len(userInput)):
    for i in aList:
        if (i == userInputList[letterExists]):
            letterExists +=1

if (letterExists == len(userInput)):
        print("This word can be made using your tiles")

use "if i in userInputList"...will work here since length differ here what you are referring in loop — Narendra
– Narendra, Commented Apr 4, 2018 at 11:45

xtofl · Accepted Answer · 2018-04-04 11:45:30Z

1

letterExists < len(userInput) only guarantees that there is 1 more letter that can be processed, but you may iterate more than 1 time by means of the for loop.

By the way, you can write this condition very nicely using set:

the_set = set(["B", "S", ...])
if(all(x in the_set for x in userInput)):
   ...

answered Apr 4, 2018 at 11:45

xtofl

41.7k13 gold badges112 silver badges203 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Laurent H. · Accepted Answer · 2018-04-04 15:46:55Z

0

Looking at your code and without trying to do better, I found that a break is missing after the incrementation of letterExists. Here is the fixed code:

aList = ["B" , "S" , "N" , "O" , "E" , "U" , "T" ]
userInput = "TOE"
userInputList = list(userInput)
letterExists = 0

while (letterExists < len(userInput)):
    for i in aList:
        if (i == userInputList[letterExists]):
            letterExists +=1
            break

if (letterExists == len(userInput)):
        print("This word can be made using your tiles")

However, a better pythonic solution is the following (same as xtofl's answer):

aList = ["B" , "S" , "N" , "O" , "E" , "U" , "T" ]
userInput = "TOF"

a = all([letter in aList for letter in userInput])

if (a):
    print("This word can be made using your tiles")

edited Apr 4, 2018 at 15:46

answered Apr 4, 2018 at 11:53

Laurent H.

6,5761 gold badge21 silver badges40 bronze badges

Comments

shlomta1 · Accepted Answer · 2018-04-04 11:50:20Z

0

You can use python magic and write it like this:

len([chr for chr in userInput if chr in aList]) == len(userInput)

answered Apr 4, 2018 at 11:50

shlomta1

1481 silver badge11 bronze badges

Collectives™ on Stack Overflow

While loop: list index out of range

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related