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Formula to determine brightness of RGB color
... → sqrt( 0.299*R^2 + 0.587*G^2 + 0.114*B^2 ) (thanks to @MatthewHerbst) [3]
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How to delete migration files in Rails 3
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Chris Frederick
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answered Oct 6 '10 at 16:56
Fábio BatistaFábio B...
How to empty/destroy a session in rails?
...ides.rubyonrails.org/security.html#session-expiry
– m33lky
Feb 24 '12 at 7:14
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Should I use document.createDocumentFragment or document.createElement
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edited Aug 3 '14 at 13:39
answered Aug 3 '10 at 14:04
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Which characters need to be escaped when using Bash?
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edited May 29 '17 at 15:34
answered Nov 18 '13 at 16:47
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Calculate difference between two datetimes in MySQL
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3 Answers
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Remove rows with duplicate indices (Pandas DataFrame and TimeSeries)
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I would suggest using the duplicated method on the Pandas Index itself:
df3 = df3[~df3.index.duplicated(keep='first')]
While all the other methods work, the currently accepted answer is by far the least performant for the provided example. Furthermore, while the groupby method is only slightly les...
Check if value exists in Postgres array
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337
Simpler with the ANY construct:
SELECT value_variable = ANY ('{1,2,3}'::int[])
The right op...
Multiple levels of 'collection.defaultdict' in Python
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347
Use:
from collections import defaultdict
d = defaultdict(lambda: defaultdict(int))
This wil...
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 13: ordinal not in range(128)
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The file is being read as a bunch of strs, but it should be unicodes. Python tries to implicitl...