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How does python numpy.where() work?
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How do they achieve internally that you are able to pass something like x > 5 into a method?
The short answer is that they don't.
Any sort of logical operation on a numpy array returns a boolean array. (i.e. __gt__, __lt__, etc all return ...
When do I use a dot, arrow, or double colon to refer to members of a class in C++?
...ect of a class that overloads operator-> (common such types are smart pointers and iterators), then the meaning is whatever the class designer implemented. To conclude: With a->b, if a is a pointer, b will be a member of the object the pointer a refers to. If, however, a is an object of a clas...
Is it better to use std::memcpy() or std::copy() in terms to performance?
... of its information. When you call std::copy, the function keeps the types intact. memcpy operates on void *, which discards almost all useful information. For instance, if I pass in an array of std::uint64_t, the compiler or library implementer may be able to take advantage of 64-bit alignment with...
When are C++ macros beneficial? [closed]
... FILE generates a string constant, which will be concatenated with the ":" into a single string by the pre-processor.
– Frank Szczerba
Mar 19 '09 at 23:59
12
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Non-recursive depth first search algorithm
...rsion you can't delete node's memory in visit function. This algorithm can convert tree to single-linked list by using "first_child" pointer. Than you can walk through it and free node's memory without recursion.
– puchu
Feb 20 '14 at 16:38
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Aborting a shell script if any command returns a non-zero value?
...r part of an && or || list.
See the bash(1) man page on the "set" internal command for more details.
I personally start almost all shell scripts with "set -e". It's really annoying to have a script stubbornly continue when something fails in the middle and breaks assumptions for the rest ...
How can a Java variable be different from itself?
...Float.NaN:
float x = Float.NaN; // <--
if (x == x) {
System.out.println("Ok");
} else {
System.out.println("Not ok");
}
Not ok
You can do the same with Double.NaN.
From JLS §15.21.1. Numerical Equality Operators == and !=:
Floating-point equality testing is performed in accordance...
How much is the overhead of smart pointers compared to normal pointers in C++?
How much is the overhead of smart pointers compared to normal pointers in C++11? In other words, is my code going to be slower if I use smart pointers, and if so, how much slower?
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PostgreSQL LIKE query performance variations
...out creating an index on the lowercase value of the field. That way I can convert the query text to lowercase on the backend before querying.
– Jason
Oct 14 '09 at 15:03
add ...
How to measure elapsed time in Python?
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Is there a nice way of converting resulting execturion time in seconds to something like HH:MM::SS?
– Danijel
Feb 4 '16 at 10:05
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