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PHP Regex to check date is in YYYY-MM-DD format
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23 Answers
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How does zip(*[iter(s)]*n) work in Python?
... arguments for a function call. Therefore you're passing the same iterator 3 times to zip(), and it pulls an item from the iterator each time.
x = iter([1,2,3,4,5,6,7,8,9])
print zip(x, x, x)
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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...
Which is faster in Python: x**.5 or math.sqrt(x)?
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93
math.sqrt(x) is significantly faster than x**0.5.
import math
N = 1000000
%%timeit
for i in r...
Generate all permutations of a list without adjacent equal elements
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30
This is along the lines of Thijser's currently incomplete pseudocode. The idea is to take the m...
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...
jQuery select by attribute using AND and OR operators
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AND operation
a=$('[myc="blue"][myid="1"][myid="3"]');
OR operation, use commas
a=$('[myc="blue"],[myid="1"],[myid="3"]');
As @Vega commented:
a=$('[myc="blue"][myid="1"],[myc="blue"][myid="3"]');
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Markdown: continue numbered list
In the following markdown code I want item 3 to start with list number 3. But because of the code block in between markdown starts this list item as a new list. Is there any way to prevent that behaviour?
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Why is pow(a, d, n) so much faster than a**d % n?
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edited Jan 3 '13 at 6:08
answered Jan 3 '13 at 6:03
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How do you get the magnitude of a vector in Numpy?
...ray -- say x.norm() -- but oh well).
import numpy as np
x = np.array([1,2,3,4,5])
np.linalg.norm(x)
You can also feed in an optional ord for the nth order norm you want. Say you wanted the 1-norm:
np.linalg.norm(x,ord=1)
And so on.
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