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Fastest way to replace NAs in a large data.table
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Here's a solution using data.table's := operator, building on Andrie and Ramnath's answers.
require(data.table) # v1.6.6
require(gdata) # v2.8.2
set.seed(1)
dt1 = create_dt(2e5, 200, 0.1)
dim(dt1)
[1] 200000 200 # more columns than Ramnath's answer which h...
How to use the IEqualityComparer
...get all of them without duplication. I created a compare class to do this work, but the execution of the function causes a big delay from the function without distinct, from 0.6 sec to 3.2 sec!
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Why am I seeing “TypeError: string indices must be integers”?
...with both learning python and trying to get github issues into a readable form. Using the advice on How can I convert JSON to CSV? I came up with this:
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Copy file remotely with PowerShell
...ess to those UNC paths. If you use local filesystem paths, then you
are cornering yourself into running the script on a specific computer.
This only works when a PowerShell session runs under the user who has rights to both administrative shares.
I suggest to use regular network share on server...
Reverse a string in Java
I have "Hello World" kept in a String variable named hi .
45 Answers
45
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What is an idempotent operation?
...idempotent operation is one that has no additional effect if it is called more than once with the same input parameters. For example, removing an item from a set can be considered an idempotent operation on the set.
In mathematics, an idempotent operation is one where f(f(x)) = f(x). For example, t...
Clearing intent
My Android app is getting called by an intent that is passing information (pendingintent in statusbar).
20 Answers
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What is the difference between Int and Integer?
...old any number no
matter how big, up to the limit of
your machine's memory…. This means you never have
arithmetic overflows. On the other
hand it also means your arithmetic is
relatively slow. Lisp users may
recognise the "bignum" type here.
"Int" is the more common 32 or 64 bit
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Clear a terminal screen for real
...= 27 == ESC
So this becomes <ESC>c which is the VT100 escape code for resetting the terminal. Here is some more information on terminal escape codes.
Edit
Here are a few other ways of doing it...
printf "\ec" #\e is ESC in bash
echo -en "\ec" #thanks @Jonathon Reinhart.
# -e Enable int...
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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