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How to reorder data.table columns (without copying)
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Use setcolorder():
library(data.table)
x <- data.table(a = 1:3, b = 3:1, c = runif(3))
x
# a b c
# [1,] 1 3 0.2880365
# [2,] 2 2 0.7785115
# [3,] 3 1 0.3297416
setcolorder(x, c("c", "b", "a"))
x
# c b a
# [1,] 0.2880365 3 1
# [2,] 0.7785115 2 2
# [3,] 0.329741...
What does 'synchronized' mean?
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edited Mar 30 '18 at 7:18
Paolo Forgia
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Installing Ruby Gem in Windows
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73
I recommend you just use rubyinstaller
It is recommended by the official Ruby page - see https:...
Can you delete multiple branches in one command with Git?
...lean up my local repository, which has a ton of old branches: for example 3.2 , 3.2.1 , 3.2.2 , etc.
29 Answers
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“cannot resolve symbol R” in Android Studio
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Iterate a list with indexes in Python
...ld swear I've seen the function (or method) that takes a list, like this [3, 7, 19] and makes it into iterable list of tuples, like so: [(0,3), (1,7), (2,19)] to use it instead of:
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How do I compare version numbers in Python?
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386
Use packaging.version.parse.
>>> from packaging import version
>>> version....
Is there an equivalent for the Zip function in Clojure Core or Contrib?
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(map vector '(1 2 3) '(4 5 6))
does what you want:
=> ([1 4] [2 5] [3 6])
Haskell needs a collection of zipWith (zipWith3, zipWith4, ...) functions, because they all need to be of a specific type; in particular, the number of input lis...
栈和队列的面试题Java实现 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...队列的如下考试内容：（1）栈的创建（2）队列的创建（3）两个栈实现一...栈和队列：
面试的时候，栈和队列经常会成对出现来考察。本文包含栈和队列的如下考试内容：
（1）栈的创建
（2）队列的创建
（3）两个栈实现一...