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Reshaping data.frame from wide to long format
... idvar = c("Code", "Country"),
timevar = "Year",
times = 1950:1954)
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Ruby optional parameters
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130
This isn't possible with ruby currently. You can't pass 'empty' attributes to methods. The cl...
Changing iframe src with Javascript
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126
In this case, it's probably because you are using the wrong brackets here:
document.getElemen...
Why does Bootstrap set the line-height property to 1.428571429?
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Factors in R: more than an annoyance?
... same. However, you end up with warnings in your code:
lm(Petal.Length ~ -1 + Species, data=iris)
# Call:
# lm(formula = Petal.Length ~ -1 + Species, data = iris)
# Coefficients:
# Speciessetosa Speciesversicolor Speciesvirginica
# 1.462 4.260 5.552 ...
How to update a value, given a key in a hashmap?
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PreparedStatement IN clause alternatives?
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195
An analysis of the various options available, and the pros and cons of each is available here....
How to control the line spacing in UILabel
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edited Jan 5 '18 at 8:31
Bart van Kuik
3,8212626 silver badges4444 bronze badges
answered Ap...
How are multi-dimensional arrays formatted in memory?
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147
A static two-dimensional array looks like an array of arrays - it's just laid out contiguously...
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 ...