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dplyr summarise: Equivalent of “.drop=FALSE” to keep groups with zero length in output
...e .drop argument that does just what you asked for:
df = data.frame(a=rep(1:3,4), b=rep(1:2,6))
df$b = factor(df$b, levels=1:3)
df %>%
group_by(b, .drop=FALSE) %>%
summarise(count_a=length(a))
#> # A tibble: 3 x 2
#> b count_a
#> <fct> <int>
#> 1 1 ...
How to get the list of files in a directory in a shell script?
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C# DateTime to UTC Time without changing the time
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6/1/2011 4:08:40 PM Local
6/1/2011 4:08:40 PM Utc
from
DateTime dt = DateTime.Now; ...
Create array of all integers between two numbers, inclusive, in Javascript/jQuery [duplicate]
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Bash empty array expansion with `set -u`
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How to efficiently build a tree from a flat structure?
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arrayfun can be significantly slower than an explicit loop in matlab. Why?
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You can get the idea by running other versions of your code. Consider explicitly writing out t...
Which HTML elements can receive focus?
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Andrew Tobilko
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answered Oct 21 '09 at 11:19
bobincebobince
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Difference between float and decimal data type
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