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What is the difference between ${var}, “$var”, and “${var}” in the Bash shell?
...parameter is a positional parameter with more than one digit…
Let's test:
$ set -- {0..100}
$ echo $22
12
$ echo ${22}
20
Huh. Neat. I honestly didn't know that before writing this (I've never had more than 9 positional parameters before.)
Of course, you also need braces to do the powerfu...
jQuery .hasClass() vs .is()
...
Update:
I committed a test following a comment and four upvotes to very comment. It turns out that what I had said is the correct answer. Here is the result:
http://jsperf.com/hasclass-vs-is-so
The is is multi-purpose, you can for example do is(...
What characters are forbidden in Windows and Linux directory names?
.../, '\0'; the name . was the current directory, of course). It was used to test the Bourne shell and routinely wrought havoc on unwary programs such as backup programs.
Other people have covered the Windows rules.
Note that MacOS X has a case-insensitive file system.
1 It was Kernighan & Pik...
How to find all positions of the maximum value in a list?
...iciencies pointed out by @John Machin. For (2) I attempted to optimize the tests based on guesstimated probability of occurrence of each condition and inferences allowed from predecessors. It was a little tricky figuring out the proper initialization values for max_val and max_indices which worked f...
instantiate a class from a variable in PHP?
...
class Test {
public function yo() {
return 'yoes';
}
}
$var = 'Test';
$obj = new $var();
echo $obj->yo(); //yoes
share
|
...
#if DEBUG vs. Conditional(“DEBUG”)
... you should pretty much never use either. If you really need something for testing and debugging, figure out a way to make that testability seperate from the actual production code.
Abstract the scenarios with mocking in unit tests, make one off versions of things for one off scenarios you want to ...
How do you use script variables in psql?
...ontrary to Bryce's report, it seems to work fine for me. CREATE TABLE test (name VARCHAR, age INT); INSERT INTO test (name, age) VALUES ('Jack', 21), ('Jill', 20); WITH vars AS (SELECT N'Jack' AS name, 21 AS age) SELECT test.* FROM test, vars WHERE test.name = vars.name and te...
How to explain dependency injection to a 5-year-old? [closed]
...ing this way becomes problematic especially when you want to perform unit testing.
The main problem comes when you need to test one particular object, you need to create an instance of other object, and most likely you need to create an instance of yet other object to do that. The chain may become...
String.Replace ignoring case
... don't have to escape the replacement string.
Here is a small fiddle that tests the code:
using System;
using System.Text.RegularExpressions;
public class Program
{
public static void Main()
{
var tests = new[] {
new { Input="abcdef", Search="abc", Replacem...
Django dynamic model fields
...ill Hardy's talk at DjangoCon 2011 (watch it!) are nevertheless robust and tested in production (relevant source code).
First to implement this was Michael Hall.
Yes, this is magic, with these approaches you can achieve fully dynamic Django apps, models and fields with any relational database back...