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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 ...
arrayfun can be significantly slower than an explicit loop in matlab. Why?
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101
You can get the idea by running other versions of your code. Consider explicitly writing out t...
Lombok is not generating getter and setter
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144
When starting with a fresh eclipse installation you, in fact, need to "install" Lombok before ...
in javascript, how can i get the last character in a string [duplicate]
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183
Since in Javascript a string is a char array, you can access the last character by the length ...
Rails mapping array of hashes onto single hash
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163
You could compose Enumerable#reduce and Hash#merge to accomplish what you want.
input = [{"te...
Linux error while loading shared libraries: cannot open shared object file: No such file or director
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18 Answers
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Active
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Calling shell functions with xargs
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175
Exporting the function should do it (untested):
export -f echo_var
seq -f "n%04g" 1 100 | xar...
Difference between float and decimal data type
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12 Answers
12
Active
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Passing parameters in rails redirect_to
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174
Just append them to the options:
redirect_to controller: 'thing', action: 'edit', id: 3, some...
Dictionaries and default values
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edited Jan 23 '19 at 5:30
Solomon Ucko
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