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Converting RGB to grayscale/intensity
When converting from RGB to grayscale, it is said that specific weights to channels R, G, and B ought to be applied. These weights are: 0.2989, 0.5870, 0.1140.
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Select first row in each GROUP BY group?
As the title suggests, I'd like to select the first row of each set of rows grouped with a GROUP BY .
17 Answers
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Why does sed not replace all occurrences?
If I run this code in bash:
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Correct way to populate an Array with a Range in Ruby
I am working through a book which gives examples of Ranges being converted to equivalent arrays using their "to_a" methods
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What is the difference between a pseudo-class and a pseudo-element in CSS?
Things like a:link or div::after ...
8 Answers
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Bulk insert with SQLAlchemy ORM
Is there any way to get SQLAlchemy to do a bulk insert rather than inserting each individual object. i.e.,
10 Answers
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What is the difference between concurrency, parallelism and asynchronous methods?
Concurrency is having two tasks run in parallel on separate threads. However, asynchronous methods run in parallel but on the same 1 thread. How is this achieved? Also, what about parallelism?
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Shortcuts in Objective-C to concatenate NSStrings
Are there any shortcuts to ( stringByAppendingString: ) string concatenation in Objective-C, or shortcuts for working with NSString in general?
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@synthesize vs @dynamic, what are the differences?
What are the differences between implementing a @property with @dynamic or @synthesize ?
8 Answers
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