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How to generate all permutations of a list?
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33 Answers
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How do I make a list of data frames?
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This isn't related to your question, but you want to use = and not <- within the function ca...
Using numpy to build an array of all combinations of two arrays
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131
In newer version of numpy (>1.8.x), numpy.meshgrid() provides a much faster implementation:
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Fastest way to list all primes below N
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35 Answers
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Average of 3 long integers
I have 3 very large signed integers.
12 Answers
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What does axis in pandas mean?
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399
It specifies the axis along which the means are computed. By default axis=0. This is consisten...
Base64 length calculation?
...log2(64) = 6).
Therefore 4 chars are used to represent 4 * 6 = 24 bits = 3 bytes.
So you need 4*(n/3) chars to represent n bytes, and this needs to be rounded up to a multiple of 4.
The number of unused padding chars resulting from the rounding up to a multiple of 4 will obviously be 0, 1, 2 or...
Assign multiple columns using := in data.table, by group
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This now works in v1.8.3 on R-Forge. Thanks for highlighting it!
x <- data.table(a = 1:3, b = 1:6)
f <- function(x) {list("hi", "hello")}
x[ , c("col1", "col2") := f(), by = a][]
# a b col1 col2
# 1: 1 1 hi hello
# 2: 2 2 hi hello
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How do I use floating-point division in bash?
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– Nahuel Fouilleul
Oct 4 '12 at 7:32
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What's the difference between tilde(~) and caret(^) in package.json?
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See the NPM docs and semver docs:
~version “Approximately equivalent to version”, will upda...