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Sort rows in data.table in decreasing order on string key `order(-x,v)` gives error on data.table 1.
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Update
data.table v1.9.6+ now supports OP's original attempt and the following answer is no longer necessary.
You can use DT[order(-rank(x), y)].
x y v
1: c 1 7
2: c 3 8
3: c 6 9
4: b 1 1
5: b 3 2
6: b 6 3
7: a 1 4
8: a 3 5
9: a 6 6
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Create UIActionSheet 'otherButtons' by passing in array, not varlist
...utton titles on a UIActionSheet. Unfortunately, the otherButtonTitles: argument in the method invocation takes a variable length list of strings, not an array.
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Rails: How to get the model class name based on the controller class name?
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class HouseBuyersController < ApplicationController
def index
@model_name = controller_name.classify
end
end
This is often needed when abstracting controller actions:
class HouseBuyersController < ApplicationController
def index
# Equivalent of @house_buyers = HouseBuyer....
What's the difference between .so, .la and .a library files?
I know an .so file is a kind of dynamic library (lots of threads can share such libraries so there is no need to have more than one copy of it in memory). But what is the difference between .a and .la ? Are these all static libraries?
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Image loaded event in for ng-src in AngularJS
I have images looking like <img ng-src="dynamically inserted url"/> . When a single image is loaded, I need to apply iScroll refresh() method so that to make image scrollable.
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ruby system command check exit code
I have a bunch of system calls in ruby such as the following and I want to check their exit codes simultaneously so that my script exits out if that command fails.
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Rails check if yield :area is defined in content_for
...nt to do a conditional rendering at the layout level based on the actual template has defined content_for(:an__area) , any idea how to get this done?
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How can I get the intersection, union, and subset of arrays in Ruby?
I want to create different methods for a class called Multiset .
3 Answers
3
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How do I revert master branch to a tag in git?
We have branches origin and develop.
The initial state of master was tagged at tag_ABC .
2 Answers
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How to replace a single word under cursor?
How do I replace a word under the cursor in Vim.
5 Answers
5
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