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Find the day of a week
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df = data.frame(date=c("2012-02-01", "2012-02-01", "2012-02-02"))
df$day <- weekdays(as.Date(df$date))
df
## date day
## 1 2012-02-01 Wednesday
## 2 2012-02-01 Wednesday
## 3 2012-02-02 Thursday
Edit: Just to show another way...
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Error installing libv8: ERROR: Failed to build gem native extension
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16 Answers
16
Active
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Extract value of attribute node via XPath
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//Parent[@id='1']/Children/child/@name
Your original child[@name] means an element child which has an attribute name. You want child/@name.
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JS: Check if date is less than 1 hour ago?
Is there a way to check if a date is less than 1 hour ago?
7 Answers
7
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PHP: How to send HTTP response code?
...TP response line and lets you replace that with a custom one
header("HTTP/1.1 200 OK");
However, this requires special treatment for (Fast)CGI PHP:
$sapi_type = php_sapi_name();
if (substr($sapi_type, 0, 3) == 'cgi')
header("Status: 404 Not Found");
else
header("HTTP/1.1 404 Not Found");...
How to pass command line arguments to a rake task
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18 Answers
18
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Simpler way to create dictionary of separate variables?
...) for name in ['some','list','of','vars'] )
Example
>>> some= 1
>>> list= 2
>>> of= 3
>>> vars= 4
>>> dict( (name,eval(name)) for name in ['some','list','of','vars'] )
{'list': 2, 'some': 1, 'vars': 4, 'of': 3}
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App Inventor 2 图表组件实战：5种图表类型+动态数据绑定，手把手做出专业...
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基础概念
App Inventor 2 的图表体系由三个组件构成：
1. Chart（图表容器）：负责画布渲染，决定图表类型（折线图、面积图、散点图、条形图、饼图）
2. ChartData2D（二维数据序列）：挂载在Chart上，负责存储和管理x-y数据对...
Identifying the dependency relationship for python packages installed with pip
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187
You could try pipdeptree which displays dependencies as a tree structure e.g.:
$ pipdeptree
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