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jQuery attr vs prop?
...his isn't just another What's the difference question , I have done some tests(http://jsfiddle.net/ZC3Lf/) modifying the prop and attr of <form action="/test/"></form> with the output being:
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Check existence of input argument in a Bash shell script
... [ -z "$1" ]
then
echo "No argument supplied"
fi
The -z switch will test if the expansion of "$1" is a null string or not. If it is a null string then the body is executed.
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What is the purpose of “&&” in a shell command?
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See the example:
mkdir test && echo "Something" > test/file
Shell will try to create directory test and then, only if it was successfull will try create file inside it.
So you may interrupt a sequence of steps if one of them failed.
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How to change the background color of the options menu?
...round">@color/overflow_background</item>
...
</style>
Tested from API 4.2 to 5.0.
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Adding an identity to an existing column
...ess than 5 seconds.
Here's a code sample of how it works.
CREATE TABLE Test
(
id int identity(1,1),
somecolumn varchar(10)
);
INSERT INTO Test VALUES ('Hello');
INSERT INTO Test VALUES ('World');
-- copy the table. use same schema, but no identity
CREATE TABLE Test2
(
id int NO...
Checking for NULL pointer in C/C++ [closed]
...
In my experience, tests of the form if (ptr) or if (!ptr) are preferred. They do not depend on the definition of the symbol NULL. They do not expose the opportunity for the accidental assignment. And they are clear and succinct.
Edit: As Soa...
How do I get the directory that a program is running from?
...ve path. So for example I have this directory structure:
main
----> test
----> src
----> bin
and I want to compile my source code to bin and write a log to test I can just add this line to my code.
std::string pathToWrite = base + "/../test/test.log";
I have tried this approach...
differentiate null=True, blank=True in django
...null=True because it allows two different kinds of "blanky" values. I just tested this behaviour with Django 1.8/MySQL 5.6
– Edward D'Souza
Aug 3 '16 at 17:14
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How to check if an object is nullable?
... boxed, but you can with generics:
- so how about below. This is actually testing type T, but using the obj parameter purely for generic type inference (to make it easy to call) - it would work almost identically without the obj param, though.
static bool IsNullable<T>(T obj)
{
if (obj =...
What's the fastest way to merge/join data.frames in R?
... the precise computation can make a huge difference on which package is fastest. For example, we do a merge and an aggregate below. We see that the results are nearly reversed for the two. In the first example from fastest to slowest we get: data.table, plyr, merge and sqldf whereas in the second...