CODEWITHSUNDEEP
pythontypeerrorunused-variables
Nam Hoang
Nam Hoang

Reputation: 39

Unused variables and TypeError: cannot unpack non-iterable int object

Hello I'm a newbie at python. In my function, I keep getting warnings of unused variables r,g,b,a. Can someone explain it for me?

def encode_image(self,img, msg):
        length = len(msg)
        if length > 255:
            print("text too long! (don't exeed 255 characters)")
            return False
        encoded = img.copy()
        width, height = img.size
        index = 0
        for row in range(height):
            for col in range(width):
                if img.mode != 'RGB':
                    r, g, b ,a = img.getpixel((col, row))
                elif img.mode == 'RGB':
                    r, g, b = img.getpixel((col, row))
                # first value is length of msg
                if row == 0 and col == 0 and index < length:
                    asc = length
                elif index <= length:
                    c = msg[index -1]
                    asc = ord(c)
                else:
                    asc = b
                encoded.putpixel((col, row), (r, g , asc))
                index += 1
        return encoded

Unused variable 'a' pylint(unused-variable)
Unused variable 'r' pylint(unused-variable)
Unused variable 'g' pylint(unused-variable)
Unused variable 'b' pylint(unused-variable)

   r, g, b ,a = img.getpixel((col, row))
TypeError: cannot unpack non-iterable int object

Upvotes: 0

Views: 200

Answers (1)

Nitish
Nitish

Reputation: 462

Your check if img.mode !='RGB' is not sufficient. Seems like your image is greyscale, hence getpixel() will only return one integer value, hence it cannot split an integer into 4 variables. (i.e. can't unpack to 4 variables)

Use img.getbands() to find how many bands are there and then unpack accordingly.

Upvotes: 1

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