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Objective-C : BOOL vs bool
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From the definition in objc.h:
#if (TARGET_OS_IPHONE && __LP64__) || TARGET_OS_WATCH
typedef bool BOOL;
#else
typedef signed char BOOL;
// BOOL is explicitly signed so @encode(BOOL) == "c" rather than "C"
// even if -funsigned-char is used.
#endif
#defin...
What are the details of “Objective-C Literals” mentioned in the Xcode 4.4 release notes?
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This part is new. Expression Literals
When you have an expression (M_PI / 16 for example) you should put it inside parenthesis.
This syntax works for numeral expressions, booleans, finding an index in a (C-) string, boolean values, enum constants, and even character strings!
NSNumber *piO...
What's the deal with a leading underscore in PHP class methods?
...private with an underscore. In some older classes you'll see /**private*/ __foo() { to give it some extra weight.
I've never heard of developers prefacing all their methods with underscores, so I can't begin to explain what causes that.
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Why can't (or doesn't) the compiler optimize a predictable addition loop into a multiplication?
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It does now -- at least, clang does:
long long add_100k_signed(int *data, int arraySize)
{
long long sum = 0;
for (int c = 0; c < arraySize; ++c)
if (data[c] >= 128)
for (int i = 0; i < 100000; ++i)
sum += data[c];
re...
Characters allowed in a URL
...738 specification:
Thus, only alphanumerics, the special characters "$-_.+!*'(),", and
reserved characters used for their reserved purposes may be used
unencoded within a URL.
EDIT: As @Jukka K. Korpela correctly points out, this RFC was updated by RFC 3986.
This has expanded and clarified...
How do I calculate square root in Python?
...ethod can be computed as: sqrt = x**(float(1)/2)
– VM_AI
Sep 28 '18 at 10:41
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How to print a percentage value in python?
...If you don't want integer division, you can import Python3's division from __future__:
>>> from __future__ import division
>>> 1 / 3
0.3333333333333333
# The above 33% example would could now be written without the explicit
# float conversion:
>>> print "{0:.0f}%".format...
“x not in y” or “not x in y”
...am' not in 'spam and eggs'
>>> dis.dis(notin)
2 0 LOAD_CONST 1 ('ham')
3 LOAD_CONST 2 ('spam and eggs')
6 COMPARE_OP 7 (not in)
9 POP_TOP
10 LOAD_CONST 0 (...
How do I partially update an object in MongoDB so the new object will overlay / merge with the exist
...e data then?
You know you can do the following:
db.collection.update( { _id:...} , { $set: someObjectWithNewData }
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Django DB Settings 'Improperly Configured' Error
...--settings=mysite.settings (or whatever settings module you use)
Set DJANGO_SETTINGS_MODULE environment variable in your OS to mysite.settings
(This is removed in Django 1.6) Use setup_environ in the python interpreter:
from django.core.management import setup_environ
from mysite import settings
s...