大约有 40,000 项符合查询结果（耗时：0.0534秒） [XML]
Do I set properties to nil in dealloc when using ARC?
...
@zeiteisen: No. unsafe_unretained is exactly equivalent to an assign property and is the normal behavior for delegate relationships under MRR, and these need to be nilled out.
– Lily Ballard
Mar 7 '12 at 20:2...
How can I add reflection to a C++ application?
...re are some handy macros to help with typed expressions:
#define REM(...) __VA_ARGS__
#define EAT(...)
// Retrieve the type
#define TYPEOF(x) DETAIL_TYPEOF(DETAIL_TYPEOF_PROBE x,)
#define DETAIL_TYPEOF(...) DETAIL_TYPEOF_HEAD(__VA_ARGS__)
#define DETAIL_TYPEOF_HEAD(x, ...) REM x
#define DETAIL_TYP...
Why can't (or doesn't) the compiler optimize a predictable addition loop into a multiplication?
...
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...
How to invoke the super constructor in Python?
...on-3.x the process has been simplified:
Python-2.x
class A(object):
def __init__(self):
print "world"
class B(A):
def __init__(self):
print "hello"
super(B, self).__init__()
Python-3.x
class A(object):
def __init__(self):
print("world")
class B(A):
def __init__(self):
print...
MD5 algorithm in Objective-C
...ons.h"
#import <CommonCrypto/CommonDigest.h> // Need to import for CC_MD5 access
@implementation NSString (MyAdditions)
- (NSString *)md5
{
const char *cStr = [self UTF8String];
unsigned char result[CC_MD5_DIGEST_LENGTH];
CC_MD5( cStr, (int)strlen(cStr), result ); // This is the m...
ZSH complains about RVM __rvm_cleanse_variables: function definition file not found
...
searched for "whats 'zcompdump' for" while diagnosing the __rvm_cleanse_variables issue... two birds, one search. +1's to everyone.
– max
Mar 21 '15 at 18:54
...
Dashed line border around UIView
...nother method if you like sublayers. In your custom view's init, put this (_border is an ivar):
_border = [CAShapeLayer layer];
_border.strokeColor = [UIColor colorWithRed:67/255.0f green:37/255.0f blue:83/255.0f alpha:1].CGColor;
_border.fillColor = nil;
_border.lineDashPattern = @[@4, @2];
[self....
mysql_config not found when installing mysqldb python interface
...but it is not mysql itself. And apparently mySQLdb needs the command 'mysql_config', so you need to install that first.
Can you confirm that you did or did not install mysql itself, by running "mysql" from the shell? That should give you a response other than "mysql: command not found".
Which lin...
Why is Python running my module when I import it, and how do I stop it?
...is:
# stuff to run always here such as class/def
def main():
pass
if __name__ == "__main__":
# stuff only to run when not called via 'import' here
main()
See What is if __name__ == "__main__" for?
It does require source control over the module being imported, however.
Happy coding.
...
How can I do a line break (line continuation) in Python?
...s are acceptable:
with open('/path/to/some/file/you/want/to/read') as file_1, \
open('/path/to/some/file/being/written', 'w') as file_2:
file_2.write(file_1.read())
Another such case is with assert statements.
Make sure to indent the continued line appropriately. The preferre...