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Fastest way to replace NAs in a large data.table
I have a large data.table , with many missing values scattered throughout its ~200k rows and 200 columns. I would like to re code those NA values to zeros as efficiently as possible.
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Define a lambda expression that raises an Exception
How can I write a lambda expression that's equivalent to:
6 Answers
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How to darken a background using CSS?
I have an element with text in it. Whenever I decrease the opacity, then I decrease the opacity of the WHOLE body. Is there any way I can just make the background-image darker, and not everything else?
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Extracting specific columns in numpy array
This is an easy question but say I have an MxN matrix. All I want to do is extract specific columns and store them in another numpy array but I get invalid syntax errors.
Here is the code:
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How to pip install a package with min and max version range?
I'm wondering if there's any way to tell pip, specifically in a requirements file, to install a package with both a minimum version ( pip install package>=0.2 ) and a maximum version which should never be installed (theoretical api: pip install package<0.3 ).
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How should I validate an e-mail address?
What's a good technique for validating an e-mail address (e.g. from a user input field) in Android? org.apache.commons.validator.routines.EmailValidator doesn't seem to be available. Are there any other libraries doing this which are included in Android already or would I have to use RegExp?
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Drop rows with all zeros in pandas data frame
I can use pandas dropna() functionality to remove rows with some or all columns set as NA 's. Is there an equivalent function for dropping rows with all columns having value 0?
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List of lists changes reflected across sublists unexpectedly
I needed to create a list of lists in Python, so I typed the following:
14 Answers
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Multiple linear regression in Python
I can't seem to find any python libraries that do multiple regression. The only things I find only do simple regression. I need to regress my dependent variable (y) against several independent variables (x1, x2, x3, etc.).
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Mapping two integers to one, in a unique and deterministic way
Imagine two positive integers A and B. I want to combine these two into a single integer C.
18 Answers
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