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Alternatives to dispatch_get_current_queue() for completion blocks in iOS 6?
...appealing, but ultimately not a great idea. That queue could be a low priority queue, the main queue, or some other queue with odd properties.
My favorite approach to this is to say "the completion block runs on an implementation defined queue with these properties: x, y, z", and let the block disp...
Does PNG contain EXIF data like JPG?
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Edit: Version 1.5.0 (July 2017) of the Extensions to the PNG 1.2 Specification has finally added an EXIF chunk. It remains to be seen if encoders-decoders begin to support it.
Original: PNG does not embed EXIF info. It allows,...
Insert line break inside placeholder attribute of a textarea?
...e', 'This is a line \nthis should be a new line');
Then you could remove it on focus and apply it back (if empty) on blur. Something like this
var placeholder = 'This is a line \nthis should be a new line';
$('textarea').attr('value', placeholder);
$('textarea').focus(function(){
if($(this)...
Change / Add syntax highlighting for a language in Sublime 2/3
...ing the .sublime-package zip file format to store all the default settings it's not very straightforward to edit the individual files.
Unfortunately, not all themes contain all scopes, so you'll need to play around with different ones to find one that looks good, and gives you the highlighting you'...
Does “untyped” also mean “dynamically typed” in the academic CS world?
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Yes, this is standard practice in academic literature. To understand it, it helps to know that the notion of "type" was invented in the 1930s, in the context of lambda calculus (in fact, even earlier, in the context of set theory). Since then, a whole branch of computa...
What is “stdafx.h” used for in Visual Studio?
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All C++ compilers have one serious performance problem to deal with. Compiling C++ code is a long, slow process.
Compiling headers included on top of C++ files is a very long, slow process. Compiling the huge header structures that form part of Windows API and other large API libraries i...
How to validate a url in Python? (Malformed or not)
I have url from the user and I have to reply with the fetched HTML.
10 Answers
10
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What's the difference between a proc and a lambda in Ruby?
...g lambda {} gives you a proc that checks the number of arguments passed to it. From ri Kernel#lambda:
Equivalent to Proc.new, except the resulting Proc objects check the number of parameters passed when called.
An example:
p = Proc.new {|a, b| puts a**2+b**2 } # => #<Proc:0x3c7d28@(irb)...
How do I remove  from the beginning of a file?
I have a CSS file that looks fine when I open it using gedit , but when it's read by PHP (to merge all the CSS files into one), this CSS has the following characters prepended to it: 
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Create a CSV File for a user in PHP
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Try:
header("Content-type: text/csv");
header("Content-Disposition: attachment; filename=file.csv");
header("Pragma: no-cache");
header("Expires: 0");
echo "record1,record2,record3\n";
die;
etc
Edit: Here's a snippet of code I use to optionally encode CSV fields:
function maybeEnc...