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Difference between assertEquals and assertSame in phpunit?
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Reports an error identified by $message if the two variables $expected and $actual do not have the same type and value."
And as you can see in the example below the above excerpt, they are passing '2204' and 2204, which will fail using assertSame because one is a string and one is an int, basi...
What is a NullPointerException, and how do I fix it?
What are Null Pointer Exceptions ( java.lang.NullPointerException ) and what causes them?
12 Answers
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How to skip over an element in .map()?
...tion would have kept it.
update — This question gets a lot of attention, and I'd like to add the following clarifying remark. The purpose of .map(), as a concept, is to do exactly what "map" means: transform a list of values into another list of values according to certain rules. Just as a paper m...
Very large matrices using Python and NumPy
NumPy is an extremely useful library, and from using it I've found that it's capable of handling matrices which are quite large (10000 x 10000) easily, but begins to struggle with anything much larger (trying to create a matrix of 50000 x 50000 fails). Obviously, this is because of the massive memo...
What is a race condition?
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A race condition occurs when two or more threads can access shared data and they try to change it at the same time. Because the thread scheduling algorithm can swap between threads at any time, you don't know the order in which the threads will attempt to access the shared data. Therefore, the re...
Java HashMap performance optimization / alternative
...or every object:
public int hashCode() {
// assume that both a and b are sorted
return a[0] + powerOf52(a[1], 1) + powerOf52(b[0], 2) + powerOf52(b[1], 3) + powerOf52(b[2], 4);
}
public static int powerOf52(byte b, int power) {
int result = b;
for (int i = 0; i < p...
Why is there huge performance hit in 2048x2048 versus 2047x2047 array multiplication?
...L is always power of 2.
The six comes from fact that 2^6 == 64 bytes is standard size of cache line.
Now what does this mean? Well it means that if I have address X and address Y and
(X >> 6) - (Y >> 6) is divisible by L (i.e. some large power of 2), they will be stored in the same ca...
Step-by-step debugging with IPython
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You can use IPython's %pdb magic. Just call %pdb in IPython and when an error occurs, you're automatically dropped to ipdb. While you don't have the stepping immediately, you're in ipdb afterwards.
This makes debugging individual functions easy, as you can just load a file with %load...
Why doesn't Python have a sign function?
I can't understand why Python doesn't have a sign function. It has an abs builtin (which I consider sign 's sister), but no sign .
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Adb Devices can't find my phone [closed]
...ying to get adb to see my Samsung Fascinate phone so that I can install my Android apps via usb to the phone. I am using osx 10.6.7.
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