大约有 15,000 项符合查询结果（耗时：0.0225秒） [XML]
Computational complexity of Fibonacci Sequence
I understand Big-O notation, but I don't know how to calculate it for many functions. In particular, I've been trying to figure out the computational complexity of the naive version of the Fibonacci sequence:
...
Combining two expressions (Expression)
I have two expressions of type Expression<Func<T, bool>> and I want to take to OR, AND or NOT of these and get a new expression of the same type
...
How to check that a string is an int, but not a double, etc.?
PHP has an intval() function that will convert a string to an integer. However I want to check that the string is an integer beforehand, so that I can give a helpful error message to the user if it's wrong. PHP has is_int() , but that returns false for string like "2" .
...
How do I make the return type of a method generic?
Is there a way to make this method generic so I can return a string, bool, int, or double? Right now, it's returning a string, but if it's able find "true" or "false" as the configuration value, I'd like to return a bool for example.
...
How to declare an array in Python?
...le = []
Now variable refers to an empty list*.
Of course this is an assignment, not a declaration. There's no way to say in Python "this variable should never refer to anything other than a list", since Python is dynamically typed.
*The default built-in Python type is called a list, not an arr...
Creating a blocking Queue in .NET?
I have a scenario where I have multiple threads adding to a queue and multiple threads reading from the same queue. If the queue reaches a specific size all threads that are filling the queue will be blocked on add until an item is removed from the queue.
...
How do I get a class instance of generic type T?
I have a generics class, Foo<T> . In a method of Foo , I want to get the class instance of type T , but I just can't call T.class .
...
C++: const reference, before vs after type-specifier
What is the difference between the arguments in:
7 Answers
7
...
“for loop” with two variables? [duplicate]
...a nested for loop, use:
import itertools
for i, j in itertools.product(range(x), range(y)):
# Stuff...
If you just want to loop simultaneously, use:
for i, j in zip(range(x), range(y)):
# Stuff...
Note that if x and y are not the same length, zip will truncate to the shortest list. As...
C++ templates that accept only certain types
In Java you can define generic class that accept only types that extends class of your choice, eg:
14 Answers
...