大约有 43,100 项符合查询结果（耗时：0.0398秒） [XML]
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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Print a file, skipping the first X lines, in Bash [duplicate]
I have a very long file which I want to print, skipping the first 1,000,000 lines, for example.
13 Answers
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Exit a Script On Error
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138
Are you looking for exit?
This is the best bash guide around.
http://tldp.org/LDP/abs/html/
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Moving average or running mean
... NumPy function or module for Python that calculates the running mean of a 1D array given a specific window?
27 Answers
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How can I get Docker Linux container information from within the container itself?
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14 Answers
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How do I get the fragment identifier (value after hash #) from a URL?
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No need for jQuery
var type = window.location.hash.substr(1);
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What's the difference between eval, exec, and compile?
...ed as an expression, so it really does not return anything).
In versions 1.0 - 2.7, exec was a statement, because CPython needed to produce a different kind of code object for functions that used exec for its side effects inside the function.
In Python 3, exec is a function; its use has no effec...
C# 5 async CTP: why is internal “state” set to 0 in generated code before EndAwait call?
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Okay, I finally have a real answer. I sort of worked it out on my own, but only after Lucian Wis...
How to reshape data from long to wide format
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11 Answers
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