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Cluster analysis in R: determine the optimal number of clusters

..., calinski.best, "\n") # 5 clusters! Four. Determine the optimal model and number of clusters according to the Bayesian Information Criterion for expectation-maximization, initialized by hierarchical clustering for parameterized Gaussian mixture models # See http://www.jstatsoft.org/v18/i06/pap...
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How to normalize a NumPy array to within a certain range?

...io /= np.max(np.abs(audio),axis=0) image *= (255.0/image.max()) Using /= and *= allows you to eliminate an intermediate temporary array, thus saving some memory. Multiplication is less expensive than division, so image *= 255.0/image.max() # Uses 1 division and image.size multiplications i...
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Modifying a subset of rows in a pandas dataframe

Assume I have a pandas DataFrame with two columns, A and B. I'd like to modify this DataFrame (or create a copy) so that B is always NaN whenever A is 0. How would I achieve that? ...
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Calculate the center point of multiple latitude/longitude coordinate pairs

Given a set of latitude and longitude points, how can I calculate the latitude and longitude of the center point of that set (aka a point that would center a view on all points)? ...
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The simplest possible JavaScript countdown timer? [closed]

... I have two demos, one with jQuery and one without. Neither use date functions and are about as simple as it gets. Demo with vanilla JavaScript function startTimer(duration, display) { var timer = duration, minutes, seconds; setInterval(functio...
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GroupBy pandas DataFrame and select most common value

... two. To clean the data I have to group by data frame by first two columns and select most common value of the third column for each combination. ...
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Initialising an array of fixed size in python [duplicate]

...ets the requirements of the question because you have a defined size array and you can index one of the five elements without getting an IndexError. This is the closest thing to the C expression. – user2233706 Oct 26 '14 at 17:43 ...
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How do I generate random numbers in Dart?

How do I generate random numbers using Dart? 13 Answers 13 ...
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How to stop app that node.js express 'npm start'

... npm help npm-scripts prestop, stop, poststop: Run by the npm stop command. Set one of the above in your package.json, and then use npm stop npm help npm-stop You can make this really simple if you set in app.js, process.title = myApp; And, then in scripts.json, "scripts": { "star...
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Check that an email address is valid on iOS [duplicate]

...rict - http://blog.logichigh.com/2010/09/02/validating-an-e-mail-address/ And because categories are just better, you could also add an interface: @interface NSString (emailValidation) - (BOOL)isValidEmail; @end Implement @implementation NSString (emailValidation) -(BOOL)isValidEmail { BOO...