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Get the index of the nth occurrence of a string?
...t of n method invocations - you won't actually be checking any case twice, if you think about it. (IndexOf will return as soon as it finds the match, and you'll keep going from where it left off.)
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Handling warning for possible multiple enumeration of IEnumerable
...y to this method, only for you to enumerate it twice (getting potentially different results each time?)
The semantic missing here is that a caller, who perhaps doesn't take time to read the details of the method, may assume you only iterate once - so they pass you an expensive object. Your method s...
Filter dict to contain only certain keys?
...t[your_key] for your_key in your_keys }
Uses dictionary comprehension.
If you use a version which lacks them (ie Python 2.6 and earlier), make it dict((your_key, old_dict[your_key]) for ...). It's the same, though uglier.
Note that this, unlike jnnnnn's version, has stable performance (depends ...
Checking if a list is empty with LINQ
...e "best" (taking both speed and readability into account) way to determine if a list is empty? Even if the list is of type IEnumerable<T> and doesn't have a Count property.
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How to convert C# nullable int to int
... v1 == null ? default(int) : v1;
...which is in turn syntax sugar for an if/else:
if(v1==null)
v2 = default(int);
else
v2 = v1;
Also, as of .NET 4.0, Nullable<T> has a "GetValueOrDefault()" method, which is a null-safe getter that basically performs the null-coalescing shown above...
Handling click events on a drawable within an EditText
...al int DRAWABLE_RIGHT = 2;
final int DRAWABLE_BOTTOM = 3;
if(event.getAction() == MotionEvent.ACTION_UP) {
if(event.getRawX() >= (editComment.getRight() - editComment.getCompoundDrawables()[DRAWABLE_RIGHT].getBounds().width())) {
// your action here
...
How to mkdir only if a directory does not already exist?
...dir -p foo/bar/baz
will create directories foo, foo/bar, and foo/bar/baz if they don't exist.
Some implementation like GNU mkdir include mkdir --parents as a more readable alias, but this is not specified in POSIX/Single Unix Specification and not available on many common platforms like macOS, va...
Why doesn't indexOf work on an array IE8?
... works fine on Opera, Firefox and Chrome. However, in IE8 it fails on the if ( allowed.indexOf(ext[1]) == -1) part.
7 Ans...
Use of Finalize/Dispose method in C#
...);
}
protected virtual void Dispose(bool disposing)
{
if (disposing)
{
// get rid of managed resources
}
// get rid of unmanaged resources
}
// only if you use unmanaged resources directly in B
//~B()
//{
// Dispose(...
Custom exception type
Can I define custom types for user-defined exceptions in JavaScript? If so, how would I do it?
13 Answers
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