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Does a dot have to be escaped in a character class (square brackets) of a regular expression?
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Git repository broken after computer died
My computer went dead and now one of my git repositories is broken. When I try to checkout master it tells me:
15 Answers
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How can I convert an RGB image into grayscale in Python?
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How about doing it with Pillow:
from PIL import Image
img = Image.open('image.png').convert('LA')
img.save('greyscale.png')
Using matplotlib and the formula
Y' = 0.2989 R + 0.5870 G + 0.1140 B
you could do:
import numpy as np
import matplotlib.pypl...
Difference between natural join and inner join
...G or ON -- and, as Jonathan Leffler pointed out, select the desired result-set columns to avoid "duplicates" if desired.
Happy coding.
(The NATURAL keyword can also be applied to LEFT and RIGHT joins, and the same applies. A NATURAL LEFT/RIGHT join is just a short syntax for a specific LEFT/RIGHT j...
ISO time (ISO 8601) in Python
I have a file. In Python, I would like to take its creation time, and convert it to an ISO time (ISO 8601) string while preserving the fact that it was created in the Eastern Time Zone (ET) .
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How to add lines to end of file on Linux
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Regular expression that matches valid IPv6 addresses
I'm having trouble writing a regular expression that matches valid IPv6 addresses, including those in their compressed form (with :: or leading zeros omitted from each byte pair).
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Heroku “psql: FATAL: remaining connection slots are reserved for non-replication superuser connectio
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You either need to increase the max_connections configuration setting or (probably better) use connection pooling to route a large number of user requests through a smaller connection pool.
https://wiki.postgresql.org/wiki/Number_Of_Database_Connections
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Skip List vs. Binary Search Tree
I recently came across the data structure known as a skip list . It seems to have very similar behavior to a binary search tree.
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Pushing read-only GUI properties back into ViewModel
...)frameworkElement.GetValue(ObserveProperty);
}
public static void SetObserve(FrameworkElement frameworkElement, bool observe)
{
frameworkElement.AssertNotNull("frameworkElement");
frameworkElement.SetValue(ObserveProperty, observe);
}
public static double GetObs...