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Reorder levels of a factor without changing order of values
I have data frame with some numerical variables and some categorical factor variables. The order of levels for those factors is not the way I want them to be.
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Batch File; List files in directory, only filenames?
This is probably a very simple question, but I'm having trouble with it. Basically, I am trying to write a Batch File and I need it to list all the files in a certain directory. The dir command will do this, but it also gives a bunch of other information; I want it to list ONLY the file names an...
How do I use itertools.groupby()?
I haven't been able to find an understandable explanation of how to actually use Python's itertools.groupby() function. What I'm trying to do is this:
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What's the difference between HEAD^ and HEAD~ in Git?
When I specify an ancestor commit object in Git, I'm confused between HEAD^ and HEAD~ .
15 Answers
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A monad is just a monoid in the category of endofunctors, what's the problem?
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That particular phrasing is by James Iry, from his highly entertaining Brief, Incomplete and Mostly Wrong History of Programming Languages, in which he fictionally attributes it to Philip Wadler.
The original quote is from Saunders Mac Lane in Categorie...
Get Slightly Lighter and Darker Color from UIColor
I was looking to be able to turn any UIColor into a gradient. The way I am intending to do this is by using Core Graphics to draw a gradient. What I am trying to do is to get a color, lets say:
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Convert RGB to RGBA over white
I have a hex color, e.g. #F4F8FB (or rgb(244, 248, 251) ) that I want converted into an as-transparent-as-possible rgba color (when displayed over white). Make sense? I'm looking for an algorithm, or at least idea of an algorithm for how to do so.
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Determine font color based on background color
Given a system (a website for instance) that lets a user customize the background color for some section but not the font color (to keep number of options to a minimum), is there a way to programmatically determine if a "light" or "dark" font color is necessary?
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How to terminate a window in tmux?
...e a window in tmux? Like the Ctrl a k shortcut in screen with Ctrl a being the prefix.
10 Answers
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Representing graphs (data structure) in Python
...e neatly represent a graph in Python ? (Starting from scratch i.e. no libraries!) What data structure (e.g. dicts/tuples/dict(tuples)) will be fast but also memory efficient? One must be able to do various graph operations on it.
As pointed out, the various graph representations might he...