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How can we match a^n b^n with Java regex?
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The answer is, needless to say, YES! You can most certainly write a Java regex pattern to match anbn. It uses a positive lookahead for assertion, and one nested reference for "counting".
Rather than immediately giving out the pattern, this answer will guide readers through the process o...
Why are there no ++ and -- operators in Python?
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It's not because it doesn't make sense; it makes perfect sense to define "x++" as "x += 1, evaluating to the previous binding of x".
If you want to know the original reason, you'll have to either wade through old Python mail...
Why is the gets function so dangerous that it should not be used?
When I try to compile C code that uses the gets() function with GCC, I get this warning:
11 Answers
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How do I check if a list is empty?
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if not a:
print("List is empty")
Using the implicit booleanness of the empty list is quite pythonic.
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What is Common Gateway Interface (CGI)?
CGI is a Common Gateway Interface. As the name says, it is a "common" gateway interface for everything. It is so trivial and naive from the name. I feel that I understood this and I felt this every time I encountered this word. But frankly, I didn't. I'm still confused.
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Checking whether a variable is an integer or not [duplicate]
...which case you want
isinstance(<var>, (int, long))
Do not use type. It is almost never the right answer in Python, since it blocks all the flexibility of polymorphism. For instance, if you subclass int, your new class should register as an int, which type will not do:
class Spam(int): pass
x ...
Understanding checked vs unchecked exceptions in Java
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Many people say that checked exceptions (i.e. these that you should explicitly catch or rethrow) should not be used at all. They were eliminated in C# for example, and most languages don't have them. So you can always throw a subclass of RuntimeException (unchecked exception)
However, I think chec...
Why do you need explicitly have the “self” argument in a Python method?
When defining a method on a class in Python, it looks something like this:
10 Answers
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How can a time function exist in functional programming?
I've to admit that I don't know much about functional programming. I read about it from here and there, and so came to know that in functional programming, a function returns the same output, for same input, no matter how many times the function is called. It's exactly like a mathematical function w...
Android accelerometer accuracy (Inertial navigation)
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You get position by integrating the linear acceleration twice but the error is horrible. It is useless in practice.
Here is an explanation why (Google Tech Talk) at 23:20. I highly recommend this video.
It is not the accelerometer noi...