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Why is “if not someobj:” better than “if someobj == None:” in Python?
I've seen several examples of code like this:
9 Answers
9
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Do I need to convert .CER to .CRT for Apache SSL certificates? If so, how?
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File extensions for cryptographic certificates aren't really as standardized as you'd expect. Windows by default treats double-clicking a .crt file as a request to import the certificate into the Windows Root Certificate store, but...
Apache is downloading php files instead of displaying them
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The correct AddType for php is application/x-httpd-php
AddType application/x-httpd-php .php
AddType application/x-httpd-php-source .phps
Also make sure your php module is loaded
LoadModule php5_module modules/mod_php55.so
When you're configurin...
How can you find the height of text on an HTML canvas?
The spec has a context.measureText(text) function that will tell you how much width it would require to print that text, but I can't find a way to find out how tall it is. I know it's based on the font, but I don't know to convert a font string to a text height.
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How to generate keyboard events in Python?
...rue)
INPUT_MOUSE = 0
INPUT_KEYBOARD = 1
INPUT_HARDWARE = 2
KEYEVENTF_EXTENDEDKEY = 0x0001
KEYEVENTF_KEYUP = 0x0002
KEYEVENTF_UNICODE = 0x0004
KEYEVENTF_SCANCODE = 0x0008
MAPVK_VK_TO_VSC = 0
# msdn.microsoft.com/en-us/library/dd375731
VK_TAB = 0x09
VK_MENU = 0x12
# C struct defi...
Multiple levels of 'collection.defaultdict' in Python
...will call the lambda which will create a new defaultdict(int). And when d[existing_key][new_key2] is accessed, a new int will be created.
– interjay
Oct 11 '13 at 12:53
11
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Best practice for Python assert
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To be able to automatically throw an error when x become less than zero throughout the function. You can use class descriptors. Here is an example:
class LessThanZeroException(Exception):
pass
class variable(object):
def __init__(self, value=0):
self.__x ...
What differences, if any, between C++03 and C++11 can be detected at run-time?
...emplate<int> struct int_ { };
template<typename T> bool isCpp0xImpl(int_<T::X>*) { return true; }
template<typename T> bool isCpp0xImpl(...) { return false; }
enum A { X };
bool isCpp0x() {
return isCpp0xImpl<A>(0);
}
You can also abuse the new keywords
struct a ...
Get difference between two lists
...t
In [5]: set([1, 2]) - set([2, 3])
Out[5]: set([1])
where you might expect/want it to equal set([1, 3]). If you do want set([1, 3]) as your answer, you'll need to use set([1, 2]).symmetric_difference(set([2, 3])).
shar...
Which SQL query is faster? Filter on Join criteria or Where clause?
...is will look like this:
SELECT *
FROM TableA a
LEFT JOIN
TableXRef x
ON x.TableAID = a.ID
AND a.ID = 1
LEFT JOIN
TableB b
ON x.TableBID = b.ID
or this:
SELECT *
FROM TableA a
LEFT JOIN
TableXRef x
ON x.TableAID = a.ID
LEFT JOIN
Table...