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How to draw a rounded Rectangle on HTML Canvas?
... For some reason, I seem to be having issues with arcTo in Firefox 3.5 and Opera 10.0. Similar to this site: ditchnet.org/canvas/CanvasRoundedCornerExample.html
– bgw
Dec 10 '09 at 0:31
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Fast ceiling of an integer division in C / C++
Given integer values x and y , C and C++ both return as the quotient q = x/y the floor of the floating point equivalent. I'm interested in a method of returning the ceiling instead. For example, ceil(10/5)=2 and ceil(11/5)=3 .
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What is the formal difference in Scala between braces and parentheses, and when should they be used?
...You may replace parenthesis with curly braces if, and only if, the method expects a single parameter. For example:
List(1, 2, 3).reduceLeft{_ + _} // valid, single Function2[Int,Int] parameter
List{1, 2, 3}.reduceLeft(_ + _) // invalid, A* vararg parameter
However, there’s more you need to know ...
What is an existential type?
I read through the Wikipedia article Existential types . I gathered that they're called existential types because of the existential operator (∃). I'm not sure what the point of it is, though. What's the difference between
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Property getters and setters
... to be computed from other instance properties. In your case, there is no x to be assigned.
Explicitly: "How can I do this without explicit backing ivars". You can't - you'll need something to backup the computed property. Try this:
class Point {
private var _x: Int = 0 // _x ->...
xkcd style graphs in MATLAB
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I see two ways to solve this: The first way is to add some jitter to the x/y coordinates of the plot features. This has the advantage that you can easily modify a plot, but you have to draw the axes yourself if you want to have them xkcdyfied (see @Rody Oldenhuis' solution). The second way is to c...
How to use filter, map, and reduce in Python 3
filter , map , and reduce work perfectly in Python 2. Here is an example:
7 Answers
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Sort a list by multiple attributes?
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A key can be a function that returns a tuple:
s = sorted(s, key = lambda x: (x[1], x[2]))
Or you can achieve the same using itemgetter (which is faster and avoids a Python function call):
import operator
s = sorted(s, key = operator.itemgetter(1, 2))
And notice that here you can use sort inst...
How do I replace NA values with zeros in an R dataframe?
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See my comment in @gsk3 answer. A simple example:
> m <- matrix(sample(c(NA, 1:10), 100, replace = TRUE), 10)
> d <- as.data.frame(m)
V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
1 4 3 NA 3 7 6 6 10 6 5
2 9 8 9 5 10 NA 2 1 7 2
3 1 1 6 3 6 ...
Callback functions in C++
...s of the standard algorithms library <algorithm> use callbacks. For example the for_each algorithm applies an unary callback to every item in a range of iterators:
template<class InputIt, class UnaryFunction>
UnaryFunction for_each(InputIt first, InputIt last, UnaryFunction f)
{
for (...