NameError: Name is Not Defined

Why This Happens

Python raises NameError when you reference a name that does not exist in the current scope. Common causes include typos, using a variable before assignment, and forgetting imports. Python is case-sensitive.

The Problem

for i in range(10):
    if i > 5:
        result = i
print(result)

The Fix

result = None
for i in range(10):
    if i > 5:
        result = i
print(result)

Step-by-Step Fix

1. 1

   Check for typos

   Python is case-sensitive: 'Result' and 'result' differ.

2. 2

   Initialize variables

   Define variables before conditional blocks.

3. 3

   Check scope

   Variables inside functions are not accessible outside.