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The difference between bracket [ ] and double bracket [[ ]] for accessing the elements of a list or
R provides two different methods for accessing the elements of a list or data.frame: [] and [[]] .
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How to get arguments with flags in Bash
I know that I can easily get positioned parameters like this in bash:
11 Answers
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Getting A File's Mime Type In Java
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edited Jul 26 '13 at 23:49
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Does a foreign key automatically create an index?
...thing akin to an index in the child table. I have a hard time believing this to be true, but can't find much out there related specifically to this.
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Formatting Decimal places in R
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Background: Some answers suggested on this page (e.g., signif, options(digits=...)) do not guarantee that a certain number of decimals are displayed for an arbitrary number. I presume this is a design feature in R whereby good scientific practice involves showing a...
What is the fastest way to send 100,000 HTTP requests in Python?
... at the python concurrence library, but cannot figure out how to write this program correctly. Has anyone come across a similar problem? I guess generally I need to know how to perform thousands of tasks in Python as fast as possible - I suppose that means 'concurrently'.
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Debugging in Clojure? [closed]
...namic fib[n] (if (< n 2) n (+ (fib (- n 1)) (fib (- n 2)))))
Then Bob is once again your uncle:
(clojure.tools.trace/dotrace [fib] (fib 3))
TRACE t4328: (fib 3)
TRACE t4329: | (fib 2)
TRACE t4330: | | (fib 1)
TRACE t4330: | | => 1
TRACE t4331: | | (fib 0)
TRACE t4331: | | => 0
TRACE t43...
How do I catch a PHP fatal (`E_ERROR`) error?
...rk for fatal ( E_ERROR ) errors, such as calling a function that doesn't exist. Is there another way to catch these errors?
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Calculating the difference between two Java date instances
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The JDK Date API is horribly broken unfortunately. I recommend using Joda Time library.
Joda Time has a concept of time Interval:
Interval interval = new Interval(oldTime, new Instant());
EDIT: By the way, Joda has two concepts: Interval...
How can I use grep to find a word inside a folder?
...d by a wildcard character
-r Recursively search subdirectories listed
. Directory for search (current directory)
grep -nr 'MobileAppSer*' . (Would find MobileAppServlet.java or MobileAppServlet.class or MobileAppServlet.txt; 'MobileAppASer*.*' is another way to do the same ...