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How to sum a variable by group
...Frequency, by=list(Category=x$Category), FUN=sum)
Category x
1 First 30
2 Second 5
3 Third 34
In the example above, multiple dimensions can be specified in the list. Multiple aggregated metrics of the same data type can be incorporated via cbind:
aggregate(cbind(x$Frequency, x$Metri...
Drawing a dot on HTML5 canvas [duplicate]
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143
For performance reasons, don't draw a circle if you can avoid it. Just draw a rectangle with a w...
Why does Math.round(0.49999999999999994) return 1?
... pathological case.2 Java 7 no longer mandates this broken implementation.3
The problem
0.5+0.49999999999999994 is exactly 1 in double precision:
static void print(double d) {
System.out.printf("%016x\n", Double.doubleToLongBits(d));
}
public static void main(String args[]) {
double a =...
Rails - controller action name to string
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339
Rails 2.X: @controller.action_name
Rails 3.1.X: controller.action_name, action_name
Rails 4....
Python nested functions variable scoping [duplicate]
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edited Oct 30 '14 at 5:16
answered Nov 7 '12 at 20:08
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CSS I want a div to be on top of everything
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dev.bv
93099 silver badges1616 bronze badges
answered Sep 14 '11 at 19:22
Skylar AndersonSkylar Anderson
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How do I install an old version of Django on virtualenv?
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3 Answers
3
Active
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How to list the size of each file and directory and sort by descending size in Bash?
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edited Jul 3 '14 at 5:13
Community♦
111 silver badge
answered Feb 7 '13 at 10:54
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How to remove an element from a list by index
...y the index of the element you want to delete:
>>> a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> del a[-1]
>>> a
[0, 1, 2, 3, 4, 5, 6, 7, 8]
Also supports slices:
>>> del a[2:4]
>>> a
[0, 1, 4, 5, 6, 7, 8, 9]
Here is the section from the tutorial.
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