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How to iterate a loop with index and element in Swift
...
Yes. As of Swift 3.0, if you need the index for each element along with its value, you can use the enumerated() method to iterate over the array. It returns a sequence of pairs composed of the index and the value for each item in the array. F...
Rotating a two-dimensional array in Python
...ider the following two-dimensional list:
original = [[1, 2],
[3, 4]]
Lets break it down step by step:
>>> original[::-1] # elements of original are reversed
[[3, 4], [1, 2]]
This list is passed into zip() using argument unpacking, so the zip call ends up being the equiva...
Flatten an Array of Arrays in Swift
...
Swift >= 3.0
reduce:
let numbers = [[1,2,3],[4],[5,6,7,8,9]]
let reduced = numbers.reduce([], +)
flatMap:
let numbers = [[1,2,3],[4],[5,6,7,8,9]]
let flattened = numbers.flatMap { $0 }
joined:
let numbers = [[1,2,3],[4],[5,6,7...
How to filter Pandas dataframe using 'in' and 'not in' like in SQL
...andas as pd
>>> df
country
0 US
1 UK
2 Germany
3 China
>>> countries_to_keep
['UK', 'China']
>>> df.country.isin(countries_to_keep)
0 False
1 True
2 False
3 True
Name: country, dtype: bool
>>> df[df.country.isin(countries_to_ke...
How can I obtain the element-wise logical NOT of a pandas Series?
... 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
In [11]: %timeit ~s
10...
Regular expression to match standard 10 digit phone number
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^(\+\d{1,2}\s)?\(?\d{3}\)?[\s.-]\d{3}[\s.-]\d{4}$
Matches the following
123-456-7890
(123) 456-7890
123 456 7890
123.456.7890
+91 (123) 456-7890
If you do not want a match on non-US numbers use
^(\+0?1\s)?\(?\d{3}\)?[\s.-]\d{3}[\s.-]\d{4}$
...
Python Dictionary Comprehension
...t; d = {n: n**2 for n in range(5)}
>>> print d
{0: 0, 1: 1, 2: 4, 3: 9, 4: 16}
If you want to set them all to True:
>>> d = {n: True for n in range(5)}
>>> print d
{0: True, 1: True, 2: True, 3: True, 4: True}
What you seem to be asking for is a way to set multiple ke...
Find element's index in pandas Series
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>>> myseries[myseries == 7]
3 7
dtype: int64
>>> myseries[myseries == 7].index[0]
3
Though I admit that there should be a better way to do that, but this at least avoids iterating and looping through the object and moves it to the C level....
How to get a specific output iterating a hash in Ruby?
...
328
hash.each do |key, array|
puts "#{key}-----"
puts array
end
Regarding order I should add...
Maven dependency for Servlet 3.0 API?
How can I tell Maven 2 to load the Servlet 3.0 API?
10 Answers
10
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