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Confusion between factor levels and factor labels
There seems to be a difference between levels and labels of a factor in R.
Up to now, I always thought that levels were the 'real' name of factor levels, and labels were the names used for output (such as tables and plots). Obviously, this is not the case, as the following example shows:
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What's the concept of and differences between Framebuffer and Renderbuffer in OpenGL?
I'm confused about concept of Framebuffer and Renderbuffer. I know that they're required to render, but I want to understand them before use.
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Why would you use Oracle database? [closed]
...ho know any other db hate Oracle, those that don't assume that all DB code and/or ORM tools are difficult to use.
If I started a business that I believed was going to scale to Amazon proportions I might consider NoSQL solutions, otherwise I'd choose PostgreSQL, SQL Server (or indeed even Sybase now...
Access-Control-Allow-Origin wildcard subdomains, ports and protocols
I'm trying to enable CORS for all subdomains, ports and protocol.
11 Answers
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Search text in fields in every table of a MySQL database
...u can peek into the information_schema schema. It has a list of all tables and all fields that are in a table. You can then run queries using the information that you have gotten from this table.
The tables involved are SCHEMATA, TABLES and COLUMNS. There are foreign keys such that you can build u...
Should image size be defined in the img tag height/width attributes or in CSS? [duplicate]
...better coding practice to define an images size in the img tag's width and height attributes?
7 Answers
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Get image data url in JavaScript?
... the same domain as the page, or has the crossOrigin="anonymous" attribute and the server supports CORS. It's also not going to give you the original file, but a re-encoded version. If you need the result to be identical to the original, see Kaiido's answer.
You will need to create a canvas eleme...
Best way to test for a variable's existence in PHP; isset() is clearly broken
...l scope variables as well, on can do a $defined_vars = get_defined_vars(); and then test via array_key_exists('v', $defined_vars);.
– Henrik Opel
Sep 27 '10 at 16:01
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What is the difference between concurrency, parallelism and asynchronous methods?
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Concurrent and parallel are effectively the same principle as you correctly surmise, both are related to tasks being executed simultaneously although I would say that parallel tasks should be truly multitasking, executed "at the same ti...
Replace all elements of Python NumPy Array that are greater than some value
I have a 2D NumPy array and would like to replace all values in it greater than or equal to a threshold T with 255.0. To my knowledge, the most fundamental way would be:
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