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Reduce, fold or scan (Left/Right)?
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372
In general, all 6 fold functions apply a binary operator to each element of a collection. The re...
How can I create a Set of Sets in Python?
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121
Python's complaining because the inner set objects are mutable and thus not hashable. The solut...
“ValueError: zero length field name in format” error in Python 3.0,3.1,3.2
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I'm gonna guess that you are running python 2.6 by accident somehow.
This feature is only available for at least 3.1 if you are using python 3, or 2.7 if you are using python 2.
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Convert a float64 to an int in Go
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213
package main
import "fmt"
func main() {
var x float64 = 5.7
var y int = int(x)
fmt.Print...
What is the ideal data type to use when storing latitude / longitude in a MySQL database?
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21 Answers
21
Active
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Should I use a data.frame or a matrix?
...e the choice.
Also:
Matrices are more memory efficient:
m = matrix(1:4, 2, 2)
d = as.data.frame(m)
object.size(m)
# 216 bytes
object.size(d)
# 792 bytes
Matrices are a necessity if you plan to do any linear algebra-type of operations.
Data frames are more convenient if you frequently refer to ...
How do I list all versions of a gem available at a remote site?
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205
Well, it was easier than I thought (well, not really, let's say as easy as it should be):
gem...
Scala: Nil vs List()
...intln (Nil equals List())
true
scala> System.identityHashCode(Nil)
374527572
scala> System.identityHashCode(List())
374527572
Nil is more idiomatic and can be preferred in most cases.
Questions?
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`elif` in list comprehension conditionals
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259
Python's conditional expressions were designed exactly for this sort of use-case:
>>>...
Haskell: Where vs. Let
...parameters of the function f (there are none) and things in outer scopes.
2: To use a where in the first example, you can introduce a second named function
that takes the x as a parameter, like this:
f = State f'
f' x = y
where y = ... x ...
or like this:
f = State f'
where
f' x = y...