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Fastest way to replace NAs in a large data.table
... 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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Strange, unexpected behavior (disappearing/changing values) when using Hash default value, e.g. Hash
...ted (e.g. hashes and strings), not just arrays.
TL;DR: Use Hash.new { |h, k| h[k] = [] } if you want the most idiomatic solution and don’t care why.
What doesn’t work
Why Hash.new([]) doesn’t work
Let’s look more in-depth at why Hash.new([]) doesn’t work:
h = Hash.new([])
h[0] <&...
Entity framework linq query Include() multiple children entities
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John Leidegren
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answered Jul 29 '10 at 18:52
NixNix
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Recommended way to embed PDF in HTML?
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Peter Mortensen
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answered Nov 15 '08 at 0:01
lubos haskolubos ...
Using i and j as variables in Matlab
... and j are both functions denoting the imaginary unit:
http://www.mathworks.co.uk/help/matlab/ref/i.html
http://www.mathworks.co.uk/help/matlab/ref/j.html
So a variable called i or j will override them, potentially silently breaking code that does complex maths.
Possible solutions include using...
Truncate (not round) decimal places in SQL Server
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JimmyJimmy
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jquery IDs with spaces
Does anyone know how to select an item in the DOM by ID with jQuery, when that ID has a space?
11 Answers
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for each loop in Objective-C for accessing NSMutable dictionary
I am finding some difficulty in accessing mutable dictionary keys and values in Objective-C.
7 Answers
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How to print a float with 2 decimal places in Java?
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You can use the printf method, like so:
System.out.printf("%.2f", val);
In short, the %.2f syntax tells Java to return your variable (val) with 2 decimal places (.2) in decimal representation of a floating-point number (f) from the start of the format spe...
How to get an array of unique values from an array containing duplicates in JavaScript? [duplicate]
...u DO need to use semicolons! jsfiddle.net/bTNc2
– jack
Nov 15 '13 at 14:52
107
It's 2014 now, so ...