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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 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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Filter rows which contain a certain string
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4 Answers
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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 ...
Determine the data types of a data frame's columns
...st few values of each variable):
str(my.data)
'data.frame': 5 obs. of 4 variables:
$ y : num 1.03 1.599 -0.818 0.872 -2.682
$ x1: int 1 2 3 4 5
$ x2: logi TRUE TRUE FALSE FALSE FALSE
$ X3: Factor w/ 5 levels "a","b","c","d",..: 1 2 3 4 5
@Gavin Simpson's approach is also streamlined, but p...
Split a vector into chunks in R
...(), split() and ceiling():
> d <- rpois(73,5)
> d
[1] 3 1 11 4 1 2 3 2 4 10 10 2 7 4 6 6 2 1 1 2 3 8 3 10 7 4
[27] 3 4 4 1 1 7 2 4 6 0 5 7 4 6 8 4 7 12 4 6 8 4 2 7 6 5
[53] 4 5 4 5 5 8 7 7 7 6 2 4 3 3 8 11 6 6 1 8 4
> m...
Applying a function to every row of a table using dplyr?
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answered Jul 14 '14 at 0:20
alexwhanalexwhan
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Objective-C 2.0 Mac和iOS开发实践指南 PDF扫描版 - 文档下载 - 清泛网 - ...
...1. C程序的结构
1.1.1. main函数
1.1.2 格式化
1.1.3 注释
1.1.4 变量和函数名
1.1.5 命名惯例
1.1.6 文件
1.2 变量
1.2.1. 整数类型
1.2.2 浮点类型
1.2.3 真值
1.2.4 初始化
1.2.5 指针
1.2.6 数组
1.2.7 字符串
1.2.8 结构
1.2.9 typedef
1.2.10 枚...
Maximum number of characters using keystrokes A, Ctrl+A, Ctrl+C and Ctrl+V
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14 Answers
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CGRidCtrl控件 学习心得 - C/C++ - 清泛网 - 专注C/C++及内核技术
...能介绍... 1
2.2 框架介绍... 2
2.3 主要类介绍... 4
2.3.1 CGridCtrl类... 4
2.3.2 CGridCellCheck类... 5
2.3.3 CGridCellCombo类... 7
2.4 控件类CGridCtrl常用函数说明... 10
2.4.1 行和列的设置... 10
2.4.2 单元格信息设置.....