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30
votes
3answers
2k views

Python Forgiveness vs. Permission and Duck Typing

In Python, I often hear that it is better to "beg forgiveness" (exception catching) instead of "ask permission" (type/condition checking). In regards to enforcing duck typing in Python, is this try: ...
28
votes
12answers
8k views

Why does PHP have interfaces?

I noticed that as of PHP5, interfaces have been added to the language. However, since PHP is so loosely typed, it seems that most of the benefits of using interfaces is lost. Why is this included in ...
11
votes
5answers
1k views

Is duck typing a subset of polymorphism

From Polymorphism on WIkipedia In computer science, polymorphism is a programming language feature that allows values of different data types to be handled using a uniform interface. From duck ...
7
votes
1answer
745 views

Duck typing, data validation and assertive programming in Python

About duck typing: Duck typing is aided by habitually not testing for the type of arguments in method and function bodies, relying on documentation, clear code and testing to ensure correct use. ...
4
votes
2answers
229 views

Should duck typing affect naming conventions?

I'm a C++/C# developer and recently I've started to learn Python. I think I understand the concept of duck typing right now except for one thing. When I'm coding in C++ or C# I sometimes create ...
4
votes
1answer
1k views

implicit vs explicit interfaces

I think I understand the actual limitations of compile-time polymorphism and run-time polymorphism. But what are the conceptual differences between explicit interfaces (run-time polymorphism. ie ...
3
votes
5answers
811 views

Are design patterns independent of programming languages?

I have been recently working on Objective C and came across use of Delegate pattern. I had seen all the patterns theoretically in Java, thanks to the Head First book. But at times looking at ...
2
votes
1answer
161 views

How should I distinguish between built-in types in Python?

I have a function that accepts either a string or a dictionary as an argument. That is, it can be called as either: lookup_person({name: "John Smith", age: 57}) or lookup_person("John Smith") My ...
1
vote
1answer
822 views

How does Django turn field name strings to field name variables?

I'm very new to python and (coming from Java) am trying to think in a "pythonic" way. I'm having trouble understanding how Django turns a function (or variable) name given in string to the actual ...