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How do I tell if a regular file does not exist in Bash?
...tmp/foo.txt ] && echo "File not found!"
– DavidWinterbottom
Sep 29 '10 at 12:09
38
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Checking for a null int value from a Java ResultSet
...yAppearingStmt.executeQuery(query);
if (rs.next()) {
iVal = rs.getInt("ID_PARENT");
if (rs.wasNull()) {
// handle NULL field value
}
}
(Edited as @martin comments below; the OP code as written would not compile because iVal is not initialised)
...
Best practices for Storyboard login screen, handling clearing of data upon logout
...
In your appDelegate.m inside your didFinishLaunchingWithOptions
//authenticatedUser: check from NSUserDefaults User credential if its present then set your navigation flow accordingly
if (authenticatedUser)
{
self.window.rootViewController = [...
How to check if a process id (PID) exists
...
To check for the existence of a process, use
kill -0 $pid
But just as @unwind said, if you're going to kill it anyway, just
kill $pid
or you will have a race condition.
If you want to ignore the text output of kill and do something based on the exit code, you can
if ! kill...
Objective-C pass block as parameter
...g the * with a ^. One way to pass a block to a method is as follows:
- (void)iterateWidgets:(void (^)(id, int))iteratorBlock;
But as you can see, that's messy. You can instead use a typedef to make block types cleaner:
typedef void (^ IteratorBlock)(id, int);
And then pass that block to a meth...
How to use the toString method in Java?
... easy for a person to read. It is
recommended that all subclasses
override this method.
The toString method for class Object
returns a string consisting of the
name of the class of which the object
is an instance, the at-sign character
`@', and the unsigned hexadecimal
representa...
Referring to the null object in Python
...singleton None.
The best way to check things for "Noneness" is to use the identity operator, is:
if foo is None:
...
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android: move a view on touch move (ACTION_MOVE)
I'd like to do a simple control: a container with a view inside. If I touch the container and I move the finger, I want to move the view to follow my finger.
...
How do I auto-reload a Chrome extension I'm developing?
...e the extension every time I modify a file it's using, which is what I was ideally looking.
– Andrey Fedorov
Oct 10 '12 at 2:55
...
Update one MySQL table with values from another
...NNER JOIN original ON (tobeupdated.value = original.value)
SET tobeupdated.id = original.id
That should do it, and really its doing exactly what yours is. However, I prefer 'JOIN' syntax for joins rather than multiple 'WHERE' conditions, I think its easier to read
As for running slow, how large a...