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R - Concatenate two dataframes?
...answered Dec 3 '11 at 2:39
dfrankowdfrankow
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Ruby on Rails console is hanging when loading
...nd Ruby on Rails have no issue. When I finally Ctrl + C I get this stack trace, which points to Spring.
4 Answers
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How to compare strings ignoring the case
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You're looking for casecmp. It returns 0 if two strings are equal, case-insensitively.
str1.casecmp(str2) == 0
"Apple".casecmp("APPLE") == 0
#=> true
Alternatively, you can convert both strings to lower case (str.downcase) and c...
What is a non-capturing group in regular expressions?
...to explain this with an example.
Consider the following text:
http://stackoverflow.com/
https://stackoverflow.com/questions/tagged/regex
Now, if I apply the regex below over it...
(https?|ftp)://([^/\r\n]+)(/[^\r\n]*)?
... I would get the following result:
Match "http://stackoverflow.com/"
...
Why is using “for…in” for array iteration a bad idea?
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5
*/
Also consider that JavaScript libraries might do things like this, which will affect any array you create:
// Somewhere deep in your JavaScript library...
Array.prototype.foo = 1;
// Now you have no idea what the below code will do.
var a = [1, 2, 3, 4, 5];
for (var x in ...
PHP 5: const vs static
...s, static variables are on the class scope (not the object) scope, but unlike a const, their values can be changed.
class ClassName {
static $my_var = 10; /* defaults to public unless otherwise specified */
const MY_CONST = 5;
}
echo ClassName::$my_var; // returns 10
echo ClassName::MY_C...
How to set HTTP headers (for cache-control)?
...or my site? Do I just put cache-control:public somewhere up in my header like this?
8 Answers
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Big O of JavaScript arrays
...cript are very easy to modify by adding and removing items. It somewhat masks the fact that most languages arrays are fixed-size, and require complex operations to resize. It seems that JavaScript makes it easy to write poorly performing array code. This leads to the question:
...
Find method references in Xcode
...top-left of the Editor. (It's the button immediately to the left of the back button).
Go to the "Callers" submenu for a list of all methods that call the selected method, and click any of them to jump to that file and method.
In pictures...
A couple of notes:
You can do this for properties ...
Null coalescing in powershell
...forms.
You might also consider wrapping it in a very simple function to make things more readable:
function Coalesce($a, $b) { if ($a -ne $null) { $a } else { $b } }
$s = Coalesce $myval "new value"
or possibly as, IfNull:
function IfNull($a, $b, $c) { if ($a -eq $null) { $b } else { $c } }
$...