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Proper use of beginBackgroundTaskWithExpirationHandler
...l need to wrap it in a background task. It's also very important that you call endBackgroundTask when you're finished - otherwise the app will be killed after its allotted time has expired.
Mine tend look something like this:
- (void) doUpdate
{
dispatch_async(dispatch_get_global_queue(DISPAT...
Is there a NumPy function to return the first index of something in an array?
...:
itemindex = numpy.where(array==item)
The result is a tuple with first all the row indices, then all the column indices.
For example, if an array is two dimensions and it contained your item at two locations then
array[itemindex[0][0]][itemindex[1][0]]
would be equal to your item and so woul...
Dynamically updating plot in matplotlib
...out the more modern animation examples in the matplotlib documentation. Finally, the animation API defines a function FuncAnimation which animates a function in time. This function could just be the function you use to acquire your data.
Each method basically sets the data property of the object be...
Styling multi-line conditions in 'if' statements? [closed]
... after a \ it might not show in your editor, and the code becomes syntactically incorrect.
– Eric O Lebigot
Jan 14 '11 at 10:26
...
Understanding exactly when a data.table is a reference to (vs a copy of) another data.table
... <- DT[,new:=1L]
because the RHS already changed DT by reference. The extra DT <- is to misunderstand what := does. You can write it there, but it's superfluous.
DT is changed by reference, by :=, EVEN WITHIN FUNCTIONS :
f <- function(X){
X[,new2:=2L]
return("something else")
}...
Is there a function to make a copy of a PHP array to another?
...ewLarsson raises a point in the comments below. PHP has a special feature called "references". They are somewhat similar to pointers in languages like C/C++, but not quite the same. If your array contains references, then while the array itself is passed by copy, the references will still resolve to...
When to use Storyboard and when to use XIBs
... segues. It's much easier to do such a change in code.
Storyboards add two extra liabilities to your project: (1) The Storyboard Editor tool that generates the storyboard XML and (2) the runtime component that parses the XML and creates UI and controller objects from it. Both parts can have bugs tha...
Warning the user/local/mysql/data directory is not owned by the mysql user
...ve</key>
<true />
<key>Label</key>
<string>com.mysql.mysqld</string>
<key>ProgramArguments</key>
<array>
<string>/usr/local/mysql/bin/mysqld_safe</string>
<string>--user=mysql</string>
&...
Why can't I use the 'await' operator within the body of a lock statement?
The await keyword in C# (.NET Async CTP) is not allowed from within a lock statement.
8 Answers
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Why can't I access DateTime->date in PHP's DateTime class?
...
This is slight faster than using format() because format() formats a timestring that has already been formatted. Especially if you do it many times in a loop.
However this is not a regular behaviour of PHP. A bugreport has already been filed as @Nile mentioned in the comments above.
...