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How to remove an element from a list by index
...y the index of the element you want to delete:
>>> a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> del a[-1]
>>> a
[0, 1, 2, 3, 4, 5, 6, 7, 8]
Also supports slices:
>>> del a[2:4]
>>> a
[0, 1, 4, 5, 6, 7, 8, 9]
Here is the section from the tutorial.
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Rails: Check output of path helper from console
... a Rails console, you can call app.post_path. This will work in Rails ~= 2.3 and >= 3.1.0.
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Two-dimensional array in Swift
...ray of arrays of Ints set to 0. Arrays size is 10x5
var arr = Array(count: 3, repeatedValue: Array(count: 2, repeatedValue: 0))
// ...and for Swift 3+:
var arr = Array(repeating: Array(repeating: 0, count: 2), count: 3)
Change element at position
arr[0][1] = 18
OR
let myVar = 18
arr[0][1] = m...
ActiveRecord, has_many :through, and Polymorphic Associations
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How to implement a queue with three stacks?
...SUMMARY
O(1) algorithm is known for 6 stacks
O(1) algorithm is known for 3 stacks, but using lazy evaluation which in practice corresponds to having extra internal data structures, so it does not constitute a solution
People near Sedgewick have confirmed they are not aware of a 3-stack solution wi...
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 ...
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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iPhone Simulator location
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143
Simulator: ~/Library/Application Support/iPhone Simulator/
You can browse simulator files from ...
How to get execution time in rails console?
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