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Can someone help me understand how this helps? I'm only a mediocre programmer, and I'm having trouble understanding the implications. It seems like you declare

by e1ven 13y ago

Can someone help me understand how this helps? I'm only a mediocre programmer, and I'm having trouble understanding the implications. It seems like you declare these like any other class. So what's the difference between this, and creating a class full of ints? If I have class Color: red = 1 blue = 2 etc, wouldn't I get the same thing? Is the difference that you don't need to instantiate an instance of it? I know I'm being dense, and I've read the PEP, but it's not quite clicking yet.

famousactress 13y ago
In this case, the attributes are not ints.. so If you defined that class functions that took it's attributes would need to accept an int, and if I passed max-int or something it'd be up to your function to go figure out whether my argument was a valid value for Color. The enum class gives you that stuff. The argument you'd expect would be instanceof(arg, Color) == True (I think that's how they did it) and if it was, you'd be assured that the value was a valid value for Color. So you could do it yourself, sure.. but to get all the little benefits, you'd have to do more coding than naming a bunch of ints in a new class.. It's subtle though. Not a wild game-changer or anything :)
- e1ven 13y ago
  Thanks.. That makes sense.. And I suppose it also helps satisfy the "explicit is better than implicit" edict, by making it clearer what you are doing.
pyre 13y ago
Read the section on IntEnums[1]: IntEnum values behave like integers in other ways you'd expect: >>> int(Shape.circle) 1 >>> ['a', 'b', 'c'][Shape.circle] 'b' >>> [i for i in range(Shape.square)] [0, 1] [1] http://www.python.org/dev/peps/pep-0435/#intenum http://www.python.org/dev/peps/pep-0435/#intenum
dietrichepp 13y ago
In addition to what famousactress said, you also get: >>> Color.red <Color.red: 1> So when you print out an enumeration, you get its name instead of just the number. This can be a big deal for debugging e.g. OpenGL code, which has a lot of enumerations. Which of the following would you prefer? >>> gl.getError() 1286 Or would you prefer, >>> gl.getError() <gl.INVALID_FRAMEBUFFER_OPERATION: 1286>

by e1ven 13y ago

famousactress 13y ago

In this case, the attributes are not ints.. so If you defined that class functions that took it's attributes would need to accept an int, and if I passed max-int or something it'd be up to your function to go figure out whether my argument was a valid value for Color. The enum class gives you that stuff. The argument you'd expect would be instanceof(arg, Color) == True (I think that's how they did it) and if it was, you'd be assured that the value was a valid value for Color. So you could do it yourself, sure.. but to get all the little benefits, you'd have to do more coding than naming a bunch of ints in a new class.. It's subtle though. Not a wild game-changer or anything :)

e1ven 13y ago
Thanks.. That makes sense.. And I suppose it also helps satisfy the "explicit is better than implicit" edict, by making it clearer what you are doing.

pyre 13y ago

Read the section on IntEnums[1]: IntEnum values behave like integers in other ways you'd expect: >>> int(Shape.circle) 1 >>> ['a', 'b', 'c'][Shape.circle] 'b' >>> [i for i in range(Shape.square)] [0, 1] [1] http://www.python.org/dev/peps/pep-0435/#intenum http://www.python.org/dev/peps/pep-0435/#intenum

dietrichepp 13y ago

In addition to what famousactress said, you also get: >>> Color.red <Color.red: 1> So when you print out an enumeration, you get its name instead of just the number. This can be a big deal for debugging e.g. OpenGL code, which has a lot of enumerations. Which of the following would you prefer? >>> gl.getError() 1286 Or would you prefer, >>> gl.getError() <gl.INVALID_FRAMEBUFFER_OPERATION: 1286>