array initialized to “None” in Python

I see a piece of python code


/*my funciton*/

does a python array get initialized to None? What does none represent ? Is the above comparision correct?I am a newbie in python and trying to relate to C++ concepts


self.matrix isn't an array, it is a dict. This is comparable to a std::map in C++. From your usage, it is like a std::map<std::pair<srcType, dstType>, valueType>. (Note that dicts can hold variant types both in the key and the value -- I'm only assuming that it'll always use a tuple of 2 elements as the key.)

And no, self.matrix isn't initialized to None. dict.get() returns None if it can't find a match. As an alternative, [] throws a KeyError exception if it can't find a match.

Need Your Help

I am having trouble determining whether two c# strings are sorted

c# string unit-testing sorting

I have created a method of determining whether two strings are sorted. All of my test cases work except for one. The code is below.

Why is numpy.all much slower than python standard all?

python numpy timeit

I wrote a script to do some rank order correlation calculations on our local cluster. The calculation involves looking two arrays, X and Y of length 5000-10000, and extracting the quantities

About UNIX Resources Network

Original, collect and organize Developers related documents, information and materials, contains jQuery, Html, CSS, MySQL, .NET, ASP.NET, SQL, objective-c, iPhone, Ruby on Rails, C, SQL Server, Ruby, Arrays, Regex, ASP.NET MVC, WPF, XML, Ajax, DataBase, and so on.