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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
Active
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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...
What is the difference between float and double?
...re calculated:
double has 52 mantissa bits + 1 hidden bit: log(253)÷log(10) = 15.95 digits
float has 23 mantissa bits + 1 hidden bit: log(224)÷log(10) = 7.22 digits
This precision loss could lead to greater truncation errors being accumulated when repeated calculations are done, e.g.
float a = 1...
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(",") ...
不同品牌的防火墙组成高可靠性集群 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...设备 ASG 425 支持OSPF BGP PIM路由协议
第二台设备SSG 520
支持BGP OSPF PIM RIP 路由协议
第一种方法
说明：两个防火墙属于不同品牌HA 等技术想都不用想了，想通过VRRP实现主备切换， juniper 我只发现了NSRP 的选项 Astarto 根本...
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...