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Is PHP's count() function O(1) or O(n) for arrays?
...
For example,
$cnt = count($array);
for ($i =0; $i < $cnt; $i++) {
foo($array[$i]);
}
Additionally, you can't always be sure count is being called on an array. If it's called on an object that implements Countable for example, the count method of that object will be called.
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How do I use CSS in Django?
...e template -- say, an image inside an image folder from /site_media/images/foo.gif.
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Check if a variable is a string in JavaScript
... against it is that it 'fails' for object-wrapped strings like new String('foo'), but that doesn't matter because object-wrapped strings are a worthless feature that you shouldn't be using. The Google style guide forbids them, Douglas Crockford wants them deprecated, and no libraries use them. Prete...
e.printStackTrace equivalent in python
... = logging.getLogger()
logger.setLevel(logging.DEBUG)
def f():
a = { 'foo': None }
# the following line will raise KeyError
b = a['bar']
def g():
f()
try:
g()
except Exception as e:
logger.error(str(e), exc_info=True)
And it will output:
'bar'
Traceback (most recent cal...
What is the difference between memmove and memcpy?
...ove can handle overlapping memory, memcpy can't.
Consider
char[] str = "foo-bar";
memcpy(&str[3],&str[4],4); //might blow up
Obviously the source and destination now overlap, we're overwriting
"-bar" with "bar". It's undefined behavior using memcpy if the source
and destination overlap ...
In Python, how do I indicate I'm overriding a method?
... is an override.
You can also explicitly extend an interface with class Foo(Interface), which will allow users to type help(Interface.method) to get an idea about the functionality your method is intended to provide.
shar...
Why can't I define a default constructor for a struct in .NET?
...would be called when it wouldn't. For instance, consider this:
MyStruct[] foo = new MyStruct[1000];
The CLR is able to do this very efficiently just by allocating the appropriate memory and zeroing it all out. If it had to run the MyStruct constructor 1000 times, that would be a lot less efficien...
jQuery.parseJSON throws “Invalid JSON” error due to escaped single quote in JSON
... Why would you need backticks? If you have a string like "foo 'bar'" then you just leave the single quotes unescaped.
– Jeff Kaufman
Sep 17 '12 at 16:55
3
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What should my Objective-C singleton look like? [closed]
...
Per my other answer below, I think you should be doing:
+ (id)sharedFoo
{
static dispatch_once_t once;
static MyFoo *sharedFoo;
dispatch_once(&once, ^ { sharedFoo = [[self alloc] init]; });
return sharedFoo;
}
...
What is the volatile keyword useful for?
...d to know how to stop it.
The pattern I use for threads is:
public class Foo extends Thread {
private volatile boolean close = false;
public void run() {
while(!close) {
// do work
}
}
public void close() {
close = true;
// interrupt here if needed
}
}
In the ab...