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What is an idempotent operation?
...ng, an idempotent operation is one that has no additional effect if it is called more than once with the same input parameters. For example, removing an item from a set can be considered an idempotent operation on the set.
In mathematics, an idempotent operation is one where f(f(x)) = f(x). For exa...
How to get an array of specific “key” in multidimensional array without looping
...s = array_map(function ($ar) {return $ar['id'];}, $users);
Before(Technically php 4.0.6+), you must create an anonymous function with create_function instead:
$ids = array_map(create_function('$ar', 'return $ar["id"];'), $users);
...
jQuery remove options from select
I have a page with 5 selects that all have a class name 'ct'. I need to remove the option with a value of 'X' from each select while running an onclick event. My code is:
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How to use NULL or empty string in SQL
...pty string. REASON: if there is ONLY whitespace, a single trim will remove all of it. For example, you don't care whether the comparison fails because what remains is "abc" or " abc".
– ToolmakerSteve
Dec 9 '16 at 20:06
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How to do a JUnit assert on a message in a logger
I have some code-under-test that calls on a Java logger to report its status.
In the JUnit test code, I would like to verify that the correct log entry was made in this logger. Something along the following lines:
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How do you run a command for each line of a file?
...teractive processing (sample)
Regarding the OP request: running chmod on all targets listed in file, xargs is the indicated tool. But for some other applications, small amount of files, etc...
Read entire file as command line argument.
If your file is not too big and all files are well named (w...
How to change the Content of a with Javascript
...extarea" name="something">This text gets removed</textarea>
For all the downvoters and non-believers:
Here's the MSDN reference
value Property: Retrieves or sets the text in the entry field of the textArea element.
Here's the MDN reference
value DOMString The raw value cont...
Most efficient conversion of ResultSet to JSON?
...tests. You could probably make it more elegant with a HashMap lookup to a callback but I doubt it would be any faster. As to memory, this is pretty slim as is.
Somehow I doubt this code is actually a critical bottle neck for memory or performance. Do you have any real reason to try to optimize it?...
How to create GUID / UUID?
I'm trying to create globally-unique identifiers in JavaScript. I'm not sure what routines are available on all browsers, how "random" and seeded the built-in random number generator is, etc.
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jQuery - get a list of values of an attribute from elements of a class
I have a class .object which has an attribute called level . I want to get a list of all the different values of level on the page so I can select the highest one.
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