Issue with Python Script

Question

I'm having an issue with my code where I get the output of:

Traceback (most recent call last):
File "1stHour.py", line 48, in
ws1.cell(column=1, row=i, value="%s" % blue_student_list[i])
IndexError: list index out of range`

# coding=utf:8
from pythonzenity import Message
from openpyxl.styles import PatternFill
from openpyxl import Workbook
import bluetooth
import time



def student_check(index):
    result = bluetooth.lookup_name(blue_address_list[index], timeout=3)
    if (result is not None):
        return True
    else:
        return False

blue_student_list = ['Name', 'Name2']
blue_address_list = ['Address', 'Address2']


redFill = PatternFill(start_color='FF0000', end_color='FF0000', fill_type='solid')
greenFill = PatternFill(start_color='00FF00', end_color='00FF00', fill_type='solid')


for i in range(0, len(blue_address_list)):

    i = i + 1

    ws1.cell(column=1, row=i, value="%s" % blue_student_list[i])
    if (student_check(i)):
       ws1.cell(column=2, row=i, value="%s" % "Present").fill = greenFill
    else:
       ws1.cell(column=2, row=i, value="%s" % "Absent").fill = redFill


Message(title="Attendance Checker",text="You can now open the Excel Document on your Desktop", timeout=3000)

I had this working but forgot to save it, so I don't have the correct way I had it before on here anymore. What can I do to prevent this error? I feel like I'm forgetting something or writing in the i = i + 1 part on my code.

Answer 1

When you do this:

for i in range(0, len(blue_address_list)):

there is no need to also do this:

i = i + 1

And doing so will cause the type of bug you see.

You seem to be doing this since the library you are using uses 1-based indexing rather than 0-based as in Python lists. But you are still using the (1 too high) i to index into a list when you do this:

blue_student_list[i]

So, instead of incrementing i a second time, pass a 1-higher value to the things that need it:

ws1.cell(column=1, row=i+1, value="%s" % blue_student_list[i])

and similarly in the other calls to ws1.cell.

This is.. unusual for a Python library, to say the least, and so it probably warrants putting a comment like this just before you first use row=i+1:

# Need row=i+1 because openPyXML uses 1-based indexing