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How do I make a matrix from a list of vectors in R?
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124
One option is to use do.call():
> do.call(rbind, a)
[,1] [,2] [,3] [,4] [,5] [,6]
[...
Regular expression that matches valid IPv6 addresses
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254
I was unable to get @Factor Mystic's answer to work with POSIX regular expressions, so I wrote o...
Remove duplicate elements from array in Ruby
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edited May 20 at 4:57
the Tin Man
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What is the ultimate postal code and zip regex?
...le IMO. But you would still be missing on the validation part: Zip code 12345 may exist, but 12346 not, maybe 12344 doesn't exist either. How do you check for that with a regex?
You can't.
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Maximum number of characters using keystrokes A, Ctrl+A, Ctrl+C and Ctrl+V
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14 Answers
14
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C++并发编程（中文版） - 文档下载 - 清泛网 - 专注C/C++及内核技术
...的并发… 1
1.1.2 并发的方法… 3
1.2 为什么使用并发… 4
1.2.1 因划分重点而使用并发… 5
1.2.2 为了提高性能而使用并发… 5
1.2.3 什么时候不使用并发… 6
1.3 在C++中使用并发和多线程… 7
1.3.1 多线程在C++中的发展历程… 7
1.3.2...
What is the optimal Jewish toenail cutting algorithm?
...ort ifilter, permutations
validseqs = ifilter(isValid, permutations([1,2,3,4,5]))
for i in validseqs:
print i
(1, 3, 5, 2, 4)
(1, 4, 2, 5, 3)
(2, 4, 1, 3, 5)
(2, 4, 1, 5, 3)
(2, 5, 3, 1, 4)
(3, 1, 4, 2, 5)
(3, 1, 5, 2, 4)
(3, 5, 1, 4, 2)
(3, 5, 2, 4, 1)
(4, 1, 3, 5, 2)
(4, 2, 5, 1, 3)
(4, 2, 5,...
How to get row from R data.frame
...for example:
#Add your data
x <- structure(list(A = c(5, 3.5, 3.25, 4.25, 1.5 ),
B = c(4.25, 4, 4, 4.5, 4.5 ),
C = c(4.5, 2.5, 4, 2.25, 3 )
),
.Names = c("A", "B", "C"),
class = "data.f...
How to select .NET 4.5.2 as a target framework in Visual Studio
I have installed .NET Framework 4.5.2 on Windows 8.1. But in Visual Studio 2013 I do not see the .NET Framework 4.5.2 option (see screenshot). How do I target my project for .NET 4.5.2?
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Assign multiple columns using := in data.table, by group
...b col1 col2
# 1: 1 1 hi hello
# 2: 2 2 hi hello
# 3: 3 3 hi hello
# 4: 1 4 hi hello
# 5: 2 5 hi hello
# 6: 3 6 hi hello
x[ , c("mean", "sum") := list(mean(b), sum(b)), by = a][]
# a b col1 col2 mean sum
# 1: 1 1 hi hello 2.5 5
# 2: 2 2 hi hello 3.5 7
# 3: 3 3 hi hello ...