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How to use Active Support core extensions
I have Active Support 3.0.3 installed and Rails 3.0.3 with Ruby 1.8.7.
5 Answers
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Relative frequencies / proportions with dplyr
...se(n = n()) %>%
mutate(freq = n / sum(n))
# am gear n freq
# 1 0 3 15 0.7894737
# 2 0 4 4 0.2105263
# 3 1 4 8 0.6153846
# 4 1 5 5 0.3846154
From the dplyr vignette:
When you group by multiple variables, each summary peels off one level of the grouping. That mak...
How do you match only valid roman numerals with a regular expression?
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16 Answers
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CSS3 Transparency + Gradient
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edited Jun 16 '12 at 16:08
umassthrower
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Passing parameters to JavaScript files
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14 Answers
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How to create custom easing function with Core Animation?
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// this should be a function that takes a time value between
// 0.0 and 1.0 (where 0.0 is the beginning of the animation
// and 1.0 is the end) and returns a scale factor where 0.0
// would produce the starting value and 1.0 would produce the
// ending value
typedef double (^KeyframeParametric...
Best way to merge two maps and sum the values of same key?
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15 Answers
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Find integer index of rows with NaN in pandas dataframe
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11 Answers
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use Winmerge inside of Git to file diff
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Update June 2015, 6 years later:
As detailed in "git mergetool winmerge", a simple git config...
C++ 读写xml方法整理（持续更新） - C/C++ - 清泛网 - 专注C/C++及内核技术
...八门，太多了，这里对常用的几种做一个总结，附demo。1、Markup 下载：
特点：C++编写的，一个.h，一个.cpp，绿色小巧，直接加入工程源码编译，只支持MFC。
<?xml version="1.0" encoding="utf-8"?>
<root>
<update ver="1.2.0" pkg="setup.exe" force...