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ActiveRecord, has_many :through, and Polymorphic Associations
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3 Answers
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How do I replace NA values with zeros in an R dataframe?
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See my comment in @gsk3 answer. A simple example:
> m <- matrix(sample(c(NA, 1:10), 100, replace = TRUE), 10)
> d <- as.data.frame(m)
V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
1 4 3 NA 3 7 6 6 10 6 5
2 9 8 9 5 10 NA 2 1 7 ...
Java lib or app to convert CSV to XML file? [closed]
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edited Feb 7 '13 at 10:36
CloudyMarble
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Is there a decorator to simply cache function return values?
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Starting from Python 3.2 there is a built-in decorator:
@functools.lru_cache(maxsize=100, typed=False)
Decorator to wrap a function with a memoizing callable that saves up to the maxsize most recent calls. It can save time when an expensive or...
Split list into multiple lists with fixed number of elements
...an iterator, but you can convert the result to a list,
scala> List(1,2,3,4,5,6,"seven").grouped(4).toList
res0: List[List[Any]] = List(List(1, 2, 3, 4), List(5, 6, seven))
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How to get execution time in rails console?
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Convert a PHP object to an associative array
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32 Answers
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iPhone Simulator location
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Simulator: ~/Library/Application Support/iPhone Simulator/
You can browse simulator files from ...
Finding the index of elements based on a condition using python list comprehension
... of a list.
>>> import numpy
>>> a = numpy.array([1, 2, 3, 1, 2, 3])
>>> a
array([1, 2, 3, 1, 2, 3])
>>> numpy.where(a > 2)
(array([2, 5]),)
>>> a > 2
array([False, False, True, False, False, True], dtype=bool)
>>> a[numpy.where(a > 2...
How to extend an existing JavaScript array with another array, without creating a new array
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The .push method can take multiple arguments. You can use the spread operator to pass all the el...