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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...
How to print a percentage value in python?
...age floating point precision type:
>>> print "{0:.0%}".format(1./3)
33%
If you don't want integer division, you can import Python3's division from __future__:
>>> from __future__ import division
>>> 1 / 3
0.3333333333333333
# The above 33% example would could now be w...
Pandas: drop a level from a multi-level column index?
...
321
You can use MultiIndex.droplevel:
>>> cols = pd.MultiIndex.from_tuples([("a", "b"), ...
How to convert floats to human-readable fractions?
Let's say we have 0.33 , we need to output 1/3 .
If we have 0.4 , we need to output 2/5 .
26 Answers
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How to upgrade PowerShell version from 2.0 to 3.0
...t is installed here is 2.0. Is it possible for me to upgrade it to version 3.0 or 4.0?
7 Answers
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count the frequency that a value occurs in a dataframe column
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13 Answers
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Multiple linear regression in Python
... my dependent variable (y) against several independent variables (x1, x2, x3, etc.).
13 Answers
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Difference between map, applymap and apply methods in Pandas
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Straight from Wes McKinney's Python for Data Analysis book, pg. 132 (I highly recommended this book):
Another frequent operation is applying a function on 1D arrays to each column or row. DataFrame’s apply method does exactly this:
In [116]: frame = DataFrame(np.random.randn(4, 3),...
How to randomly select an item from a list?
..., 'horse', 'staple']
print(secrets.choice(foo))
secrets is new in Python 3.6, on older versions of Python you can use the random.SystemRandom class:
import random
secure_random = random.SystemRandom()
print(secure_random.choice(foo))
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