Mar
1
ABCs: What are they good for?
Looking before you leap
Python is a duck-typed language, and one where you usually trust EAFP ("Easier to Ask Forgiveness than Permission") over LBYL ("Look Before You Leap"). In Java or C#, you need "interfaces" all over the place; you can't pass something to a function unless it's an instance of a type that implements that interface; in Python, as long as your object has the methods and other attributes that the function needs, no matter what type it is, everything is good.
Of course there are some occasions where you do need to LBYL. For example, say you need to do a whole set of operations or none at all. If the second one raises a TypeError after the first one succeeded, now you're in an inconsistent state.
Python is a duck-typed language, and one where you usually trust EAFP ("Easier to Ask Forgiveness than Permission") over LBYL ("Look Before You Leap"). In Java or C#, you need "interfaces" all over the place; you can't pass something to a function unless it's an instance of a type that implements that interface; in Python, as long as your object has the methods and other attributes that the function needs, no matter what type it is, everything is good.
Of course there are some occasions where you do need to LBYL. For example, say you need to do a whole set of operations or none at all. If the second one raises a TypeError after the first one succeeded, now you're in an inconsistent state.
