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What exactly does += do in python?
...r
return self.num
>>> a = Adder(2)
>>> a += 3
in __iadd__ 3
>>> a
5
Hope this helps.
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in_array multiple values
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answered Sep 24 '11 at 23:51
Mark ElliotMark Elliot
65.9k1818 gold badges132132 silver badges155155 bronze badges
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Efficient way to rotate a list in python
...method.
from collections import deque
items = deque([1, 2])
items.append(3) # deque == [1, 2, 3]
items.rotate(1) # The deque is now: [3, 1, 2]
items.rotate(-1) # Returns deque to original state: [1, 2, 3]
item = items.popleft() # deque == [2, 3]
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What is the best regular expression to check if a string is a valid URL?
... wrote my URL (actually IRI, internationalized) pattern to comply with RFC 3987 (http://www.faqs.org/rfcs/rfc3987.html). These are in PCRE syntax.
For absolute IRIs (internationalized):
/^[a-z](?:[-a-z0-9\+\.])*:(?:\/\/(?:(?:%[0-9a-f][0-9a-f]|[-a-z0-9\._~\x{A0}-\x{D7FF}\x{F900}-\x{FDCF}\x{FDF0}-\x...
pandas DataFrame: replace nan values with average of columns
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283
You can simply use DataFrame.fillna to fill the nan's directly:
In [27]: df
Out[27]:
...
What's valid and what's not in a URI query?
...aracter must be within data.
The current standard for generic URIs is RFC 3986, which has this to say:
2.2. Reserved Characters
URIs include components and subcomponents that are delimited by characters in the "reserved" set. These characters are called "reserved" because they may (or may not) be...
how does multiplication differ for NumPy Matrix vs Array classes?
...find it more trouble than it's worth, though.
For arrays (prior to Python 3.5), use dot instead of matrixmultiply.
E.g.
import numpy as np
x = np.arange(9).reshape((3,3))
y = np.arange(3)
print np.dot(x,y)
Or in newer versions of numpy, simply use x.dot(y)
Personally, I find it much more read...
Pandas: drop a level from a multi-level column index?
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321
You can use MultiIndex.droplevel:
>>> cols = pd.MultiIndex.from_tuples([("a", "b"), ...
Find intersection of two nested lists?
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If you want:
c1 = [1, 6, 7, 10, 13, 28, 32, 41, 58, 63]
c2 = [[13, 17, 18, 21, 32], [7, 11, 13, 14, 28], [1, 5, 6, 8, 15, 16]]
c3 = [[13, 32], [7, 13, 28], [1,6]]
Then here is your solution for Python 2:
c3 = [filter(lambda x: x in c1, sublist) for sublis...
Formatting Phone Numbers in PHP
...MS app and need to be able to convert the sender's phone number from +11234567890 to 123-456-7890 so it can be compared to records in a MySQL database .
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