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Does Java have a HashMap with reverse lookup?
I have data that is organized in kind of a "key-key" format, rather than "key-value". It's like a HashMap, but I will need O(1) lookup in both directions. Is there a name for this type of data structure, and is anything like this included in Java's standard libraries? (or maybe Apache Commons?)
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What is the difference between “int” and “uint” / “long” and “ulong”?
...xed with "u" are unsigned versions with the same bit sizes. Effectively, this means they cannot store negative numbers, but on the other hand they can store positive numbers twice as large as their signed counterparts. The signed counterparts do not have "u" prefixed.
The limits for int (32 bit) ar...
How to add an extra column to a NumPy array
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I think a more straightforward solution and faster to boot is to do the following:
import numpy as np
N = 10
a = np.random.rand(N,N)
b = np.zeros((N,N+1))
b[:,:-1] = a
And timings:
In [23]: N = 10
In [24]: a = np.random.rand(N,N)
In [25]: %timeit b = np.hstack((a,np.zeros((a.sh...
Ruby: Easiest Way to Filter Hash Keys?
I have a hash that looks something like this:
13 Answers
13
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What should go into an .h file?
...s".
The simplest question to ask yourself to determine what belongs where is "if I change this, will I have to change code in other files to make things compile again?" If the answer is "yes" it probably belongs in the header file; if the answer is "no" it probably belongs in the code file.
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Get URL query string parameters
What is the "less code needed" way to get parameters from a URL query string which is formatted like the following?
11 Answ...
Combined area of overlapping circles
...responding circles to form a polygon. The area of the union of the circles is the area of the polygon + the area of the circle slices defined by consecutive intersection points and the circle center in between them. You'll need to also account for any holes.
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Ruby's ||= (or equals) in JavaScript?
I love Ruby's ||= mechanism. If a variable doesn't exist or is nil , then create it and set it equal to something:
6 Ans...
Selenium WebDriver: Wait for complex page with JavaScript to load
I have a web application to test with Selenium. There is a lot of JavaScript running on page load.
This JavaScript code is not so well written but I can't change anything.
So waiting for an element to appear in the DOM with findElement() method is not an option.
I want to create a generic func...
Integer.toString(int i) vs String.valueOf(int i)
I am wondering why the method String.valueOf(int i) exists ? I am using this method to convert int into String and just discovered the Integer.toString(int i) method.
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