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Why are static variables considered evil?
...r example, instead, you made your variables non-static, and in your main() function you made a single instance of your class, and then asked your class to execute a particular function 10,000 times, once those 10,000 calls were done, and you delete your references to the single instance, all your st...
Why can I add named properties to an array as if it were an object?
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CaseyCasey
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Why do we need extern “C”{ #include } in C++?
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123
C and C++ are superficially similar, but each compiles into a very different set of code. When...
Difference between classification and clustering in data mining? [closed]
...stand machine learning with a simple analogy of a 2 year old boy. Just for fun, let’s call him Kylo Ren
Let’s assume Kylo Ren saw an elephant. What will his brain tell him ?(Remember he has minimum thinking capacity, even if he is the successor to Vader). His brain will tell him that he saw ...
How to see which commits in one branch aren't in the other?
...
For fun, I worked out that the '...' (symmetrical difference) rev-parse syntax was added in July 2006, and the documentation for it was updated in June 2008. The joy of open source!
– sehe
S...
What happens to a declared, uninitialized variable in C? Does it have a value?
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Static variables (file scope and function static) are initialized to zero:
int x; // zero
int y = 0; // also zero
void foo() {
static int x; // also zero
}
Non-static variables (local variables) are indeterminate. Reading them prior to assigning a valu...
Why it's not possible to use regex to parse HTML/XML: a formal explanation in layman's terms
... or bonbon. Matching of recursive/balanced structures make these even more fun.
Wikipedia puts this nicely, in a quote by Larry Wall:
'Regular expressions' [...] are only marginally related to real regular expressions. Nevertheless, the term has grown with the capabilities of our pattern matchi...
RegEx to find two or more consecutive chars
...Finds a consecutive repeating lower or upper case letter. Matches on "abbc123" and not "abc1223". To allow for a space between them (i.e. a ab), then include an optional space in the regex between the captured character and the repeat...
([a-z]A-Z])\s?\1
...
How to sort in-place using the merge sort algorithm?
...he rest as working area for merging.
For example like the following merge function.
void wmerge(Key* xs, int i, int m, int j, int n, int w) {
while (i < m && j < n)
swap(xs, w++, xs[i] < xs[j] ? i++ : j++);
while (i < m)
swap(xs, w++, i++);
while (...
Adding new column to existing DataFrame in Python pandas
...)
As per this example (which also includes the source code of the assign function), you can also include more than one column:
df = pd.DataFrame({'a': [1, 2], 'b': [3, 4]})
>>> df.assign(mean_a=df.a.mean(), mean_b=df.b.mean())
a b mean_a mean_b
0 1 3 1.5 3.5
1 2 4 1...