CODEWITHSUNDEEP
pythonexceptiontry-catch
John Ingles
John Ingles

Reputation: 33

Refactoring a series of nested try except blocks

I have a class called bit that codes for an svg rectangle. The class is instantiated with a variable saying what color the svg rectangle should be. I want it to accept colors in four styles. hex, rgb percent triplet, rgb integer triplet, and named. The init function then converts the color value to hex. I've got it working but it relies on a nested try except block and the exceptions thrown by the webcolors module. If one conversion fails it tries the next, and so on until it either succeeds or raises a final exception.

import svgwrite
from webcolors import name_to_hex, normalize_integer_triplet, rgb_percent_to_hex, normalize_hex, normalize_percent_triplet, rgb_to_hex
             
dwg = svgwrite.Drawing('qr.svg')

class Bit:
    def __init__(self, bit_color:str, spec:str='css3'):
        self.bit_type=1
        self.spec=spec
        try:
            self.bit_color=name_to_hex(bit_color,spec)
        except (ValueError, AttributeError):
            try:
                self.bit_color=rgb_to_hex(normalize_integer_triplet(bit_color))
            except (ValueError, TypeError):
                try:
                    self.bit_color=rgb_percent_to_hex(normalize_percent_triplet(bit_color))   
                except ValueError:
                    try:
                        self.bit_color=normalize_hex(bit_color)
                    except ValueError:
                        raise ValueError('Color not recognized!')

While this works and lets the user enter a color in the most common ways, it looks pretty ugly to me. Is there a way to refactor this?

Upvotes: 0

Views: 139

Answers (1)

Samwise
Samwise

Reputation: 71454

One possibility:

        try:
            self.bit_color=name_to_hex(bit_color, spec)
            return
        except (ValueError, AttributeError):
            pass
            
        try:
            self.bit_color=rgb_to_hex(normalize_integer_triplet(bit_color))
            return
        except (ValueError, TypeError):
            pass

        try:
            self.bit_color=rgb_percent_to_hex(normalize_percent_triplet(bit_color))   
            return
        except ValueError:
            pass

        try:
            self.bit_color=normalize_hex(bit_color)
        except ValueError:
            raise ValueError('Color not recognized!')

Upvotes: 1

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