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Minimum and maximum date
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179
From the spec, §15.9.1.1:
A Date object contains a Number indicating a particular instant in...
Relative frequencies / proportions with dplyr
...se(n = n()) %>%
mutate(freq = n / sum(n))
# am gear n freq
# 1 0 3 15 0.7894737
# 2 0 4 4 0.2105263
# 3 1 4 8 0.6153846
# 4 1 5 5 0.3846154
From the dplyr vignette:
When you group by multiple variables, each summary peels off one level of the grouping. That mak...
Extracting numbers from vectors of strings
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11 Answers
11
Active
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leading zeros in rails
...min , both integers in my application. For hr field, if the user enters "1" I would like Rails to automatically pad it to "01" before saving it to the database. Also for the min field if the user enter "0" it should put in as "00".
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How to use the 'sweep' function
...nd use in the operation defined by FUN.
For instance, if you want to add 1 to the 1st row, 2 to the 2nd, etc. of the matrix you defined, you will do:
sweep (M, 1, c(1: 4), "+")
I frankly did not understand the definition in the R documentation either, I just learned by looking up examples.
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How to perform element-wise multiplication of two lists?
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14 Answers
14
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Cleaning `Inf` values from an R dataframe
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121
Option 1
Use the fact that a data.frame is a list of columns, then use do.call to recreate a ...
How to do version numbers? [closed]
...the "unstable watchout" on there. So how would you go about versioning? Is 1.0 stable? Should the build date be in the version number? Tell me what you guys think!
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How to create a self-signed certificate with OpenSSL
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15 Answers
15
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Is it safe to check floating point values for equality to 0?
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115
It is safe to expect that the comparison will return true if and only if the double variable h...