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Pandas get topmost n records within each group
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>>> df.groupby('id').head(2)
id value
id
1 0 1 1
1 1 2
2 3 2 1
4 2 2
3 7 3 1
4 8 4 1
(Keep in mind that you might need to order/sort before, depending on your data)
EDIT: As mentioned by the questioner, use df.gro...
Emulate ggplot2 default color palette
...on(n) {
hues = seq(15, 375, length = n + 1)
hcl(h = hues, l = 65, c = 100)[1:n]
}
For example:
n = 4
cols = gg_color_hue(n)
dev.new(width = 4, height = 4)
plot(1:n, pch = 16, cex = 2, col = cols)
share
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What is the difference between 127.0.0.1 and localhost
... still have to do an actual lookup of localhost somewhere.
If you use 127.0.0.1, then (intelligent) software will just turn that directly into an IP address and use it. Some implementations of gethostbyname will detect the dotted format (and presumably the equivalent IPv6 format) and not do a looku...
Android: How to change CheckBox size?
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answered Jan 28 '10 at 7:36
moraesmoraes
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.NET 4.0 has a new GAC, why?
...the new GAC . Does it mean now we have to manage two GACs, one for .NET 2.0-3.5 applications and the other for .NET 4.0 applications?
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How to fix the uninitialized constant Rake::DSL problem on Heroku?
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205
Put this in your Rakefile above require 'rake':
require 'rake/dsl_definition'
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How can I convert a DateTime to the number of seconds since 1970?
...ateTime variable to Unix time, ie, the number of seconds since Jan 1st, 1970. It looks like a DateTime is actually implemented as the number of 'ticks' since Jan 1st, 0001.
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Java - get pixel array from image
...ation I was able to reduce the time of processing the pixels by more than 90% by just switching from the first approach to the second!
Here is a comparison I've setup to compare the two approaches:
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferByte;
import java.io.IOExceptio...
Difference between declaring variables before or in loop?
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260
Which is better, a or b?
From a performance perspective, you'd have to measure it. (And in my o...
Pandas every nth row
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207
I'd use iloc, which takes a row/column slice, both based on integer position and following norm...