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How do I get the number of elements in a list?
...turns 3.
Explanation
Everything in Python is an object, including lists. All objects have a header of some sort in the C implementation.
Lists and other similar builtin objects with a "size" in Python, in particular, have an attribute called ob_size, where the number of elements in the object is...
Where does Scala look for implicits?
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Implicits in Scala refers to either a value that can be passed "automatically", so to speak, or a conversion from one type to another that is made automatically.
Implicit Conversion
Speaking very briefly about the latter type, if one calls a method m on an object o of a class C, and that class d...
Finding the index of elements based on a condition using python list comprehension
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In Python, you wouldn't use indexes for this at all, but just deal with the values—[value for value in a if value > 2]. Usually dealing with indexes means you're not doing something the best way.
If you do need an API similar to Matlab's, you would use numpy, a packag...
How to get the currently logged in user's user id in Django?
...rs = [{user.id: user.get_name()} for user in logged_in_users]
# Query all logged in staff users based on id list
all_staff_users = CustomUser.objects.filter(is_resident=False, is_active=True, is_superuser=False)
logged_out_users = list()
# for some reason exclude() would not work co...
What is the difference between char array and char pointer in C?
...char* and char[] are different types, but it's not immediately apparent in all cases. This is because arrays decay into pointers, meaning that if an expression of type char[] is provided where one of type char* is expected, the compiler automatically converts the array into a pointer to its first el...
What tools are there for functional programming in C?
...ing in C ( not C++). Obviously, C is a procedural language and doesn't really support functional programming natively.
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MongoDB/NoSQL: Keeping Document Change History
... changes to one or more specific entities in a database. I've heard this called row versioning, a log table or a history table (I'm sure there are other names for it). There are a number of ways to approach it in an RDBMS--you can write all changes from all source tables to a single table (more of...
Any reason not to use '+' to concatenate two strings?
... Tuple would be faster - the code was just an example :) Usually long multiple string inputs are dynamic.
– Mikko Ohtamaa
Apr 6 '12 at 12:52
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Understanding typedefs for function pointers in C
...es' code which had typedefs for pointers to functions with arguments. I recall that it took me a while to get around to such a definition while trying to understand a numerical algorithm written in C a while ago. So, could you share your tips and thoughts on how to write good typedefs for pointers t...
How to convert an enum type variable to a string?
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There really is no beautiful way of doing this. Just set up an array of strings indexed by the enum.
If you do a lot of output, you can define an operator<< that takes an enum parameter and does the lookup for you.
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