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What is Java String interning?
...nterning is implemented magically and efficiently with a dedicated CONSTANT_String_info struct (unlike most other objects which have more generic representations):
A string literal is a reference to an instance of class String, and is derived from a CONSTANT_String_info structure (§4.4.3) in th...
What's the difference between lists and tuples?
...e pairs of page and line number to reference locations in a book, e.g.:
my_location = (42, 11) # page number, line number
You can then use this as a key in a dictionary to store notes on locations. A list on the other hand could be used to store multiple locations. Naturally one might want to ad...
Preloading images with JavaScript
...OP:
var preloadImage = function (url) {
try {
var _img = new Image();
_img.src = url;
} catch (e) { }
}
Standard:
function preloadImage (url) {
try {
var _img = new Image();
_img.src = url;
} catch (e) { ...
What is a regular expression for a MAC Address?
...perty \p{xdigit} includes the FULLWIDTH versions. You might prefer \p{ASCII_Hex_Digit} instead.
The answer to the question asked might be best answered — provided you have a certain venerable CPAN module installed — by typing:
% perl -MRegexp::Common -lE 'say $RE{net}{MAC}'
I show the partic...
What characters are valid for JavaScript variable names?
...mmarizing the relevant spec sections:
An identifier must start with $, _, or any character in the Unicode categories “Uppercase letter (Lu)”, “Lowercase letter (Ll)”, “Titlecase letter (Lt)”, “Modifier letter (Lm)”, “Other letter (Lo)”, or “Letter number (Nl)”.
The r...
Extract file name from path, no matter what the os/path format
...asename will be empty, so make your own function to deal with it:
def path_leaf(path):
head, tail = ntpath.split(path)
return tail or ntpath.basename(head)
Verification:
>>> paths = ['a/b/c/', 'a/b/c', '\\a\\b\\c', '\\a\\b\\c\\', 'a\\b\\c',
... 'a/b/../../a/b/c/', 'a/b/../....
Code Golf - π day
...
Perl, 95 96 99 106 109 110 119 characters:
$t+=$;=1|2*sqrt($r**2-($u-2*$_)**2),say$"x($r-$;/2).'*'x$;for 0..
($u=($r=<>)-1|1);say$t*2/$r**2
(The newline can be removed and is only there to avoid a scrollbar)
Yay! Circle version!
$t+=$;=
1|2*sqrt($r**
2-($u-2*$_)**2)
,say$"x($r-$;/2
)....
Trying to mock datetime.date.today(), but not working
...ock.patch('datetime.date.today')
def test():
datetime.date.today.return_value = date(2010, 1, 1)
print datetime.date.today()
Unfortunately, this won't work:
>>> test()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "build/bdist.macosx-...
Convert pem key to ssh-rsa format
...pub -i -mPKCS8
From the ssh-keygen docs (From man ssh-keygen):
-m key_format Specify a key format for the -i (import) or -e (export) conversion options. The supported key formats are: “RFC4716” (RFC 4716/SSH2 public or private key), “PKCS8” (PEM PKCS8 public key) or “PEM” (PEM pub...
PDO closing connection
...>connection = new PDO();
$this->connection->query('KILL CONNECTION_ID()');
$this->connection = null;
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