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How to select the row with the maximum value in each group
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Here's a data.table solution:
require(data.table) ## 1.9.2
group <- as.data.table(group)
If you want to keep all the entries corresponding to max values of pt within each group:
group[group[, .I[pt == max(pt)], by=Subject]$V1]
# Subject pt Event
# 1: 1 5 2
# 2: ...
Remove duplicate elements from array in Ruby
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array = array.uniq
uniq removes all duplicate elements and retains all unique elements in the...
How to count the frequency of the elements in an unordered list?
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Formatting a number with exactly two decimals in JavaScript
...ounds my numbers to two decimal places. But I get numbers like this: 10.8, 2.4, etc. These are not my idea of two decimal places so how I can improve the following?
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Numpy array dimensions
... ndarray.shape
Tuple of array dimensions.
Thus:
>>> a.shape
(2, 2)
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Computational complexity of Fibonacci Sequence
...b(n) as sum of time to calculate Fib(n-1) plus the time to calculate Fib(n-2) plus the time to add them together (O(1)). This is assuming that repeated evaluations of the same Fib(n) take the same time - i.e. no memoization is use.
T(n<=1) = O(1)
T(n) = T(n-1) + T(n-2) + O(1)
You solve this r...
Sorting multiple keys with Unix sort
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Use the -k option (or --key=POS1[,POS2]). It can appear multiple times and each key can have global options (such as n for numeric sort)
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Validating IPv4 addresses with regexp
...idation, but without much luck. It seemed at one point I had had it with (25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?(\.|$)){4} , but it produces some strange results:
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Split (explode) pandas dataframe string entry to separate rows
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FFMPEG (libx264) “height not divisible by 2”
...ing to encode a .mp4 video from a set of frames using FFMPEG using the libx264 codec.
7 Answers
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