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Confusion between factor levels and factor labels
...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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Are list-comprehensions and functional functions faster than “for loops”?
...specifically about map(), filter() and reduce(), but I assume you want to know about functional programming in general. Having tested this myself on the problem of computing distances between all points within a set of points, functional programming (using the starmap function from the built-in iter...
What can you use Python generator functions for?
...enerator functions, those that have a yield statement in them. I want to know what types of problems that these functions are really good at solving.
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How do I uniquely identify computers visiting my web site?
... code snippet. This document does not show how to implement it. I want to know how do I implement this so I can track unique users for my site.
– Oliver
Jul 27 '17 at 8:16
12
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How to modify a global variable within a function in bash?
... tell you, that it is impossible to fix. This is wrong, but it is a long known difficult to solve problem.
There are several ways on how to solve it best, this depends on your needs.
Here is a step by step guide on how to do it.
Passing back variables into the parental shell
There is a way to p...
Why call git branch --unset-upstream to fixup?
... version: remote-tracking branch origin/master used to exist, but does not now, so local branch source is tracking something that does not exist, which is suspicious at best—it means a different Git feature is unable to do anything for you—and Git is warning you about it. You have been getting ...
Cannot refer to a non-final variable inside an inner class defined in a different method
...pture the value in the delegate, change the value in the outer method, and now the delegate sees the new value see, stackoverflow.com/questions/271440/c-captured-variable-in-loop for the C# example of this behaviour that Java aims to avoid.
– Chris Chilvers
Aug...
Random “Element is no longer attached to the DOM” StaleElementReferenceException
...- page is refreshed, or element is removed and re-added
element.click();
Now at the point where you're clicking the element, the element reference is no longer valid. It's close to impossible for WebDriver to make a good guess about all the cases where this might happen - so it throws up its hands...
PostgreSQL: Show tables in PostgreSQL
... list all databases and users by \l command, (list other commands by \?).
Now if you want to see other databases you can change user/database by \c command like \c template1, \c postgres postgres and use \d, \dt or \dS to see tables/views/etc.
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JavaScript get clipboard data on paste event (Cross browser)
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The situation has changed since writing this answer: now that Firefox has added support in version 22, all major browsers now support accessing the clipboard data in a paste event. See Nico Burns's answer for an example.
In the past this was not generally possible in a cross-b...