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Why does comparing strings using either '==' or 'is' sometimes produce a different result?
...l reasons: it is
inherently O(n) in the length of the
strings; it typically requires reads
from several regions of memory, which
take time; and the reads fills up the
processor cache, meaning there is less
cache available for other needs. With
interned strings, a simple object
identi...
Getting number of days in a month
I have a comboBox with all of the months in it.
7 Answers
7
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What does @hide mean in the Android source code?
...);
}
return PackageManager.PERMISSION_DENIED;
}
However, we can call it by reflection:
Class c;
c = Class.forName("android.app.ActivityManager");
Method m = c.getMethod("checkUidPermission", new Class[] {String.class, int.class});
Object o = m.invoke(null, new Object[]{"android.permissio...
MySQL - length() vs char_length()
...() returns the length of the string measured in characters.
This is especially relevant for Unicode, in which most characters are encoded in two bytes. Or UTF-8, where the number of bytes varies. For example:
select length(_utf8 '€'), char_length(_utf8 '€')
--> 3, 1
As you can see the E...
What is a proper naming convention for MySQL FKs?
...constraints. If a name is not given, InnoDB creates a unique name automatically.
In any case, this is the convention that I use:
fk_[referencing table name]_[referenced table name]_[referencing field name]
Example:
CREATE TABLE users(
user_id int,
name varchar(100)
);
CREATE T...
The Concept of 'Hold space' and 'Pattern space' in sed
... line. So what happens is this:
first line is read and inserted automatically into the pattern space
on the first line, first command is not executed; h copies the first line into the hold space.
now the second line replaces whatever was in the pattern space
on the second line, first we execute G,...
How to keep index when using pandas merge
...ng multi-index, your indices will be stored as a tuple in a single column called a[copy_index]
– geekidharsh
Nov 6 '19 at 6:19
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Sending email with PHP from an SMTP server
... you are sending an e-mail through a server that requires SMTP Auth, you really need to specify it, and set the host, username and password (and maybe the port if it is not the default one - 25).
For example, I usually use PHPMailer with similar settings to this ones:
$mail = new PHPMailer();
// ...
Casting vs using the 'as' keyword in the CLR
...d within the if body.) That's slightly annoying in some cases, so if you really care about introducing the smallest number of variables possible in every scope, you might still want to use is followed by a cast.
I don't think any of the answers so far (at the time of starting this answer!) have r...
What is the difference between C, C99, ANSI C and GNU C?
...
Everything before standardization is generally called "K&R C", after the famous book, with Dennis Ritchie, the inventor of the C language, as one of the authors. This was "the C language" from 1972-1989.
The first C standard was released 1989 nationally in USA, ...