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How to sort an array in descending order in Ruby
... Here's what I found out:
#!/usr/bin/ruby
require 'benchmark'
ary = []
1000.times {
ary << {:bar => rand(1000)}
}
n = 500
Benchmark.bm(20) do |x|
x.report("sort") { n.times { ary.sort{ |a,b| b[:bar] <=> a[:bar] } } }
x.report("sort reverse") { n.times ...
Converting a list to a set changes element order
...
11 Answers
11
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Weighted random numbers
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181
There is a straightforward algorithm for picking an item at random, where items have individua...
How assignment works with Python list slice?
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116
You are confusing two distinct operation that use very similar syntax:
1) slicing:
b = a[0:2...
How do I replace NA values with zeros in an R dataframe?
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21 Answers
21
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When should I use cross apply over inner join?
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13 Answers
13
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How can I multiply all items in a list together with Python?
... that takes
a list of numbers and multiplies them together. Example:
[1,2,3,4,5,6] will give me 1*2*3*4*5*6 . I could really use your help.
...
Finding the mode of a list
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162
You can use the max function and a key. Have a look at python max function using 'key' and lam...
Move an array element from one array position to another
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31 Answers
31
Active
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How can I obtain the element-wise logical NOT of a pandas Series?
...: s = pd.Series([True, True, False, True])
In [8]: ~s
Out[8]:
0 False
1 False
2 True
3 False
dtype: bool
Using Python2.7, NumPy 1.8.0, Pandas 0.13.1:
In [119]: s = pd.Series([True, True, False, True]*10000)
In [10]: %timeit np.invert(s)
10000 loops, best of 3: 91.8 µs per loop
...