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How to get a key in a JavaScript object by its value?
...allowing me to get the key for a value, or do I have to iterate the object and find it out manually?
27 Answers
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What does O(log n) mean exactly?
I am learning about Big O Notation running times and amortized times. I understand the notion of O(n) linear time, meaning that the size of the input affects the growth of the algorithm proportionally...and the same goes for, for example, quadratic time O(n2) etc..even algorithms, such as permu...
Concatenating two one-dimensional NumPy arrays
...:
import numpy
import perfplot
perfplot.show(
setup=lambda n: numpy.random.rand(n),
kernels=[
lambda a: numpy.r_[a, a],
lambda a: numpy.stack([a, a]).reshape(-1),
lambda a: numpy.hstack([a, a]),
lambda a: numpy.concatenate([a, a]),
],
labels=["r_", "...
Get the value of an instance variable given its name
...variable_get("@#{name}")
There is no need to use + or intern; Ruby will handle this just fine. However, if you find yourself reaching into another object and pulling out its ivar, there's a reasonably good chance that you have broken encapsulation.
If you explicitly want to access an ivar, the ri...
Changing java platform on which netbeans runs
...tallation.
Modify the netbeans_jdkhome variable to point to new JDK path, and then
Restart your Netbeans.
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Impossible to Install PG gem on my mac with Mavericks
...
If you want to avoid using MacPorts, you can download the Postgres App and place it into the Application directory.
Then, specify the location of newly downloaded pg_config:
gem install pg -- --with-pg-config=/Applications/Postgres.app/Contents/Versions/latest/bin/pg_config
If you run in to...
Can I call memcpy() and memmove() with “number of bytes” set to zero?
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From the C99 standard (7.21.1/2):
Where an argument declared as size_t n specifies the length of the array for a
function, n can have the value zero on a call to that function. Unless explicitly stated
otherwise in the description o...
Unresolved specs during Gem::Specification.reset:
...was seeing this issue by just running RSpec on its own. From what I understand, this means that you have more than one version of the listed gems installed on your system, and RSpec is unsure which one to use. After uninstalling older version of the gems, the warnings went away.
You can try:
gem c...
Image Greyscale with CSS & re-color on mouse-over?
I am looking to take an icon that is colored (and will be a link) and turn it greyscale until the user places their mouse over the icon (where it would then color the image).
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Are JavaScript strings immutable? Do I need a “string builder” in JavaScript?
...on) so I wanted to test out the different methods of concatenating strings and abstracting the fastest way into a StringBuilder. I wrote some tests to see if this is true (it isn't!).
This was what I believed would be the fastest way, though I kept thinking that adding a method call may make it slo...