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Convert light frequency to RGB?
...teachers may have told us (well mine did). Too bad, but in practice not usually fatal.
– Francis Davey
May 29 '10 at 22:58
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What does the “map” method do in Ruby?
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Ahhh I get it. So .map actually mutates the array while .each just loops through the array to access the values while leaving the original array untouched?
– bigpotato
Aug 23 '12 at 4:18
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How to convert an array of strings to an array of floats in numpy?
...(or equivalently, use a list comprehension). (In Python 3, you'll need to call list on the map return value if you use map, since map returns an iterator now.)
However, if it's already a numpy array of strings, there's a better way. Use astype().
import numpy as np
x = np.array(['1.1', '2.2', '3....
Calculate the center point of multiple latitude/longitude coordinate pairs
...e of the center point of that set (aka a point that would center a view on all points)?
21 Answers
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What's the point of const pointers?
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"Help the compiler help you" is the mantra I normally chant for this.
– Flexo♦
Oct 11 '11 at 9:44
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Can you split a stream into two streams?
... @JoD It is thread-safe if heads and tails are thread-safe. Additionally, assuming the use of non-parallel streams, only the order is not guaranteed, so they are thread-safe. It's up to the programmer to fix concurrency issues, so this answer is perfectly suitable if the collections are threa...
Swapping column values in MySQL
...test s1, swap_test s2 SET s1.x=s1.y, s1.y=s2.x WHERE s1.id=s2.id;
Essentially, the 1st table is the one getting updated and the 2nd one is used to pull the old data from.
Note that this approach requires a primary key to be present.
This is my test schema:
CREATE TABLE `swap_test` (
`id` int(1...
All combinations of a list of lists
I'm basically looking for a python version of Combination of List<List<int>>
7 Answers
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Python argparse ignore unrecognised arguments
Optparse, the old version just ignores all unrecognised arguments and carries on. In most situations, this isn't ideal and was changed in argparse. But there are a few situations where you want to ignore any unrecognised arguments and parse the ones you've specified.
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How to easily initialize a list of Tuples?
I love tuples . They allow you to quickly group relevant information together without having to write a struct or class for it. This is very useful while refactoring very localized code.
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