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Code works sometimes, and sometimes it returns "list index out of range" instead

December 8, 2022

I’m getting this issue in quite a few different places throughout my code, but I’ll only post the simplest code where I’m getting this issue so I can learn from it.

My code works sometimes, and other times it doesn’t. When it doesn’t work, I get IndexError: list index out of range returned. Its in a class called Students, data is referencing a .txt file that has 800 students in it (give or take).

def SearchStudent(self, data):
    
  students = []
  with open(data, "r") as datafile:
    for line in datafile:
      datum = line.split()
      students.append(datum)
        
   searchFirstName = input('Enter students first name: ')

   for datum in students:
     if datum[1] == searchFirstName:
       print(datum)

Error seems to hit the if datum[1] == searchFirstName: part when it happens, but struggling to wrap my head around why it’s happening.

>Solution :

Revise like below to do a basic check:

for datum in students:      
    if len(datum) > 1 and datum[1] == searchFirstName:
        # note index[0] on the list would mean a list length of 1, so looking >1 to get a list containing at least an index[1]
        print(datum)