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Group by multiple columns in dplyr, using string vector input
...ike so:
data = data.frame(
asihckhdoydkhxiydfgfTgdsx = sample(LETTERS[1:3], 100, replace=TRUE),
a30mvxigxkghc5cdsvxvyv0ja = sample(LETTERS[1:3], 100, replace=TRUE),
value = rnorm(100)
)
# get the columns we want to average within
columns = names(data)[-3]
library(dplyr)
df1 <- data...
Drawable image on a canvas
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179
The good way to draw a Drawable on a canvas is not decoding it yourself but leaving it to the ...
MongoDB副本集详解 优于以往的主从模式 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...为mongodb-linux-x86_64-2.6.0
由三台虚拟机搭建，配置为单核,1G内存。实验环境如下:
MongoDB的副本集不同于以往的主从模式。
在集群Master故障的时候，副本集可以自动投票，选举出新的Master，并引导其余的Slave服务器连接新的Master...
How to check if BigDecimal variable == 0 in java?
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Underscore: sortBy() based on multiple attributes
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11 Answers
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CGContextDrawImage draws image upside down when passed UIImage.CGImage
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How does this CSS produce a circle?
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How does a border of 180 pixels with height/width-> 0px become a circle with a radius of 180 pixels?
Let's reformulate that into two questions:
Where do width and height actually apply?
Let's have a look at the areas of a typical box (sour...
Programmatically set left drawable in a TextView
... |
edited Sep 7 at 21:46
Andrew Orobator
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an...
Changing font size and direction of axes text in ggplot2
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301
Use theme():
d <- data.frame(x=gl(10, 1, 10, labels=paste("long text label ", letters[1:10])...
How to base64 encode image in linux bash / shell
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155
You need to use cat to get the contents of the file named 'DSC_0251.JPG', rather than the file...