[Solved] Why does this code raise an IndexError on Raspberry Pi when reading a QR code? from pyzbar.... Why does this code raise an IndexError on Raspberry Pi when reading a QR code? | Raspberry Pi

Raspberry Pi - Camera Module

Why does this code raise an IndexError on Raspberry Pi when reading a QR code?

from pyzbar.pyzbar import decode
from PIL import Image
img = Image.open('no_qr.png')
result = decode(img)
print(result[0].data.decode('utf-8'))

Adecode() returns None instead of list

BThe image has no QR code, so result list is empty

CImage.open failed to load image

Ddecode() returns bytes, not list

Step-by-Step Solution

Solution:

Step 1: Understand decode() output when no QR code
decode() returns an empty list if no QR codes are found in the image.
Step 2: Accessing first element causes IndexError
Accessing result[0] when list is empty causes IndexError.
Final Answer:
The image has no QR code, so result list is empty -> Option B
Quick Check:
Empty decode list causes IndexError on result[0] [OK]

Quick Trick: Check if decode result list is empty before accessing elements [OK]

Common Mistakes:

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Why does this code raise an IndexError on Raspberry Pi when reading a QR code?