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How can I view the source code for a function?
...repository or Winston Chang's github mirror.
Uwe Ligges's R news article (PDF) (p. 43) is a good general reference of how to view the source code for .Internal and .Primitive functions. The basic steps are to first look for the function name in src/main/names.c and then search for the "C-entry" na...
What's the difference between __PRETTY_FUNCTION__, __FUNCTION__, __func__?
...ction_name
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1208r5.pdf went into C++20, so we have yet another way to do it.
The documentation says:
constexpr const char* function_name() const noexcept;
6 Returns: If this object represents a position in the body of a function,
returns an im...
Is there a Google Voice API? [closed]
... as of 2019.
"pygooglevoice" can perform most of the voice functions from Python. It can send SMS. I've developed code to receive SMS messages, but the overhead is excessive given the current Google Voice interface. Each poll returns over 100K of content, so you'd use a quarter-gigabyte a day ju...
Is it better to use std::memcpy() or std::copy() in terms to performance?
...do exactly what you ask.
See this presentation on compiler optimisations (pdf).
Here's what GCC does for a simple std::copy of a POD type.
#include <algorithm>
struct foo
{
int x, y;
};
void bar(foo* a, foo* b, size_t n)
{
std::copy(a, a + n, b);
}
Here's the disassembly (with o...
Days between two dates? [duplicate]
...r days, or groups of 24 hours?
For simply 24 hours, assuming you're using Python's datetime, then the timedelta object already has a days property:
days = (a - b).days
For calendar days, you'll need to round a down to the nearest day, and b up to the nearest day, getting rid of the partial day o...
Why does pylint object to single character variable names?
I'm still getting used to python conventions and using pylint to make my code more pythonic, but I'm puzzled by the fact that pylint doesn't like single character variable names. I have a few loops like this:
...
How to store a dataframe using Pandas
...tter for interoperability, as a faster alternative to JSON, or if you have python object/text-heavy data (see this question).
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ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.al
... the two arrays to be evaluated in boolean context (by
calling __bool__ in Python3 or __nonzero__ in Python2).
Your original code
mask = ((r["dt"] >= startdate) & (r["dt"] <= enddate))
selected = r[mask]
looks correct. However, if you do want and, then instead of a and b use (a-b).any...
In which order should floats be added to get the most precise result?
...ere are still brick-and-mortar libraries around. Alternatively, buying the PDF online costs $5-$15 (depending on whether you're an ACM member). Lastly, DeepDyve seem to be offering to lend the paper for 24 hours for $2.99 (if you're new to DeepDyve, you might even be able to get it for free as part ...
Counting inversions in an array
...
In Python
# O(n log n)
def count_inversion(lst):
return merge_count_inversion(lst)[1]
def merge_count_inversion(lst):
if len(lst) <= 1:
return lst, 0
middle = int( len(lst) / 2 )
left, a = merge_cou...