IndexError：python 上的列表索引超出范围错误

Question

This is my code:

while True:
print("Type 'done' to finish receipts")
code=input("Enter item code to add:")
items =open("items.txt")
quant=input("Quantity:")
details = items.read()
detailslist = details.split("\n")
for a in detailslist:
    fire = a.split("#")
    print (fire)
    b = fire[0]
    c = fire[1]
    d = fire[2]
    dictd = {}
    dictd[b] = c + ' ' +' Quantity: '+ ' ' + quant +' '+ 'Price:' + d
    print (dictd)       

This is in items.txt:

A# Almanac2018# 18.30
B# Almanac2020# 23.80
C# Almanac2021# 16.54
D# Almanac2022# 22.25

I am getting this error:

Type 'done' to finish receipts
Enter item code to add:A
Quantity:45
['A', ' Almanac2018', ' 18.30']
{'A': ' Almanac2018  Quantity:  45 Price: 18.30'}
['B', ' Almanac2020', ' 23.80']
{'B': ' Almanac2020  Quantity:  45 Price: 23.80'}
['C', ' Almanac2021', ' 16.54']
{'C': ' Almanac2021  Quantity:  45 Price: 16.54'}
['D', ' Almanac2022', ' 22.25']
{'D': ' Almanac2022  Quantity:  45 Price: 22.25'}
['']
Traceback (most recent call last):
  File "receipt.py", line 12, in <module>
    c = fire[1]
IndexError: list index out of range

I am trying to make a program that makes a receipt of items so if you could provide any code that would be helpful. Any help would be appreciated.

Answer 1

The problem you have in your code is with the empty strings in your items.txt file. When there's an empty string, fire would resolve to [''] , which is a list of only 1 item, so you get an error when the code tries to run c = fire[1] . You can add a check to see if it's an empty line or not:

for a in detailslist:
    fire = a.split("#")
    if len(fire) > 1:
        print (fire)
        b = fire[0]
        c = fire[1]
        d = fire[2]
        dictd = {}
        dictd[b] = c + ' ' +' Quantity: '+ ' ' + quant +' '+ 'Price:' + d
        print (dictd)

Answer 2

Give a man a fish, feed him for a day... teach a man to fish.

So this isn't a fish, but it is a fishing rod (as long as your using Python v3.7 or greater):

import pdb #Only need this if python < v3.7

while True:
print("Type 'done' to finish receipts")
code=input("Enter item code to add:")
items =open("items.txt")
quant=input("Quantity:")
details = items.read()
detailslist = details.split("\n")
for a in detailslist:
    fire = a.split("#")
    print (fire)
    try:
        b = fire[0]
        c = fire[1]
        d = fire[2]
        dictd = {}
        dictd[b] = c + ' ' +' Quantity: '+ ' ' + quant +' '+ 'Price:' + d
        print (dictd)
    except:
        breakpoint()  # if Python >= v3.7
        pdb.set_trace()  # if Python < v3.7

Which means you can see the exact shape and size of "fire" when the error is being caused. Should help your debugging efforts here - and in future when other problems inevitably crop up.