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What's the difference between [ and [[ in Bash? [duplicate]
I looked at bash man page and the [[ says it uses Conditional Expressions. Then I looked at Conditional Expressions section and it lists the same operators as test (and [ ).
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How to convert String to long in Java?
...16 '18 at 15:33
Valentin Michalak
1,6491111 silver badges2323 bronze badges
answered Oct 7 '11 at 22:10
Mike C...
Dialog with transparent background in Android
How do I remove the black background from a dialog box in Android. The pic shows the problem.
20 Answers
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How to access component methods from “outside” in ReactJS?
...>
</div>
);
}
}
Note: This will only work if the child component is declared as a class, as per documentation found here: https://facebook.github.io/react/docs/refs-and-the-dom.html#adding-a-ref-to-a-class-component
Update 2019-04-01: Changed example to use a clas...
How to decide between MonoTouch and Objective-C? [closed]
...for iPhone development. Being very comfortable in C# and .Net, it seems like an appealing option, despite some of the quirkiness of the Mono stack. However, since MonoTouch costs $400, I'm somewhat torn on if this is the way to go for iPhone development.
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How can I get the line number which threw exception?
In a catch block, how can I get the line number which threw an exception?
12 Answers
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javac : command not found
...ly, which does not contain javac. For javac, you have to install the OpenJDK Development Environment. You can install java-devel or java-1.6.0-openjdk-devel, which both include javac.
By the way: you can find out which package provides javac with a yum search, e.g.
su -c 'yum provides javac'
on ...
php is null or empty?
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What you're looking for is:
if($variable === NULL) {...}
Note the ===.
When use ==, as you did, PHP treats NULL, false, 0, the empty string, and empty arrays as equal.
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How to kill/stop a long SQL query immediately?
...e state, which is almost always true except if you do certain operations like call a web service from SQLCLR. If your attention cannot reach the server is usually due to scheduler overload.
But if your query is part of a transaction that must rollback then rollback cannot be interrupted. If it take...
Integer to hex string in C++
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You can prepend the first << with << "0x" or whatever you like if you wish.
Other manips of interest are std::oct (octal) and std::dec (back to decimal).
One problem you may encounter is the fact that this produces the exact amount of digits needed to represent it. You may use setfi...