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Why is null an object and what's the difference between null and undefined?
...n short; undefined is where no notion of the thing exists; it has no type, and it's never been referenced before in that scope; null is where the thing is known to exist, but it's not known what the value is.
One thing to remember is that null is not, conceptually, the same as false or "" or such, e...
Programmatically creating Markdown tables in R with KnitR
I am just starting to learn about KnitR and the use of Markdown in generating R documents and reports. This looks to be perfect for a lot of the day to day reporting that I have to do with my job. However, one thing that I'm not seeing is an easy way to print data frames and tables using Markdown fo...
How to generate a random int in C?
Is there a function to generate a random int number in C? Or will I have to use a third party library?
27 Answers
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Using sed to mass rename files
...ld say that the easiest way to do this is to use the
prename or rename commands.
On Ubuntu, OSX (Homebrew package rename, MacPorts package p5-file-rename), or other systems with perl rename (prename):
rename s/0000/000/ F0000*
or on systems with rename from util-linux-ng, such as RHEL:
rename 0...
Syntax behind sorted(key=lambda: …)
I don't quite understand the syntax behind the sorted() argument:
9 Answers
9
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Script parameters in Bash
...arguments that you provide to a bashscript will appear in the variables $1 and $2 and $3 where the number refers to the argument. $0 is the command itself.
The arguments are seperated by spaces, so if you would provide the -from and -to in the command, they will end up in these variables too, so fo...
Is there a good reason I see VARCHAR(255) used so often (as opposed to another length)?
In multiple courses, books, and jobs, I have seen text fields defined as VARCHAR(255) as kind of the default for "shortish" text. Is there any good reason that a length of 255 is chosen so often, other than being a nice round number ? Is it a holdout from some time in the past when there was a go...
Make $JAVA_HOME easily changable in Ubuntu [closed]
In Ubuntu, I'd like to switch my JAVA_HOME environment variable back and forth between Java 5 and 6.
8 Answers
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Twitter API returns error 215, Bad Authentication Data
... to obtain following keys you need to sign up with https://dev.twitter.com and create application.
<?php
$token = 'YOUR_TOKEN';
$token_secret = 'YOUR_TOKEN_SECRET';
$consumer_key = 'CONSUMER_KEY';
$consumer_secret = 'CONSUMER_SECRET';
$host = 'api.twitter.com';
$method = 'GET';
$path = '/1.1/st...
Why would adding a method add an ambiguous call, if it wouldn't be involved in the ambiguity
...s, you have found a bug in overload resolution. The bug reproduces in C# 4 and 5; it does not reproduce in the "Roslyn" version of the semantic analyzer. I've informed the C# 5 test team, and hopefully we can get this investigated and resolved before the final release. (As always, no promises.)
A c...