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How to randomize (or permute) a dataframe rowwise and columnwise?
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Given the R data.frame:
> df1
a b c
1 1 1 0
2 1 0 0
3 0 1 0
4 0 0 0
Shuffle row-wise:
> df2 <- df1[sample(nrow(df1)),]
> df2
a b c
3 0 1 0
4 0 0 0
2 1 0 0
1 1 1 0
By default sample() randomly reorders the elements passed as the first argument. This m...
pandas DataFrame: replace nan values with average of columns
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10 Answers
10
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Get operating system info
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202
The code below could explain in its own right, how http://thismachine.info/ is able to show whi...
How to sort an array in descending order in Ruby
...Here's what I found out:
#!/usr/bin/ruby
require 'benchmark'
ary = []
1000.times {
ary << {:bar => rand(1000)}
}
n = 500
Benchmark.bm(20) do |x|
x.report("sort") { n.times { ary.sort{ |a,b| b[:bar] <=> a[:bar] } } }
x.report("sort reverse") { n.times {...
Regex to validate date format dd/mm/yyyy
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20 Answers
20
Active
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jQuery animate backgroundColor
... g.elem.style[e] = "rgb(" + [Math.max(Math.min(parseInt((g.pos * (g.end[0] - g.start[0])) + g.start[0]), 255), 0), Math.max(Math.min(parseInt((g.pos * (g.end[1] - g.start[1])) + g.start[1]), 255), 0), Math.max(Math.min(parseInt((g.pos * (g.end[2] - g.start[2])) + g.start[2]), 255), 0)].join(",") ...
Site stopped working in asp.net System.Web.WebPages.Razor.Configuration.HostSection cannot be cast t
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200
In the root Web.config make sure assemblyBinding contains the proper version for the assembly "...
Difference between numpy.array shape (R, 1) and (R,)
...required. For example, given a matrix M , if we want to do numpy.dot(M[:,0], numpy.ones((1, R))) where R is the number of rows (of course, the same issue also occurs column-wise). We will get matrices are not aligned error since M[:,0] is in shape (R,) but numpy.ones((1, R)) is in shape...
PHP Regex to check date is in YYYY-MM-DD format
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Try this.
$date="2012-09-12";
if (preg_match("/^[0-9]{4}-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])$/",$date)) {
return true;
} else {
return false;
}
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How to use a decimal range() step value?
Is there a way to step between 0 and 1 by 0.1?
33 Answers
33
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