大约有 40,000 项符合查询结果（耗时：0.0379秒） [XML]
Unsupported major.minor version 52.0 [duplicate]
...l Java 1.5 and is nowadays called "Java SE", see en.wikipedia.org/wiki/Java_Platform,_Standard_Edition
– Tim Büthe
Sep 6 '16 at 14:38
1
...
How does an underscore in front of a variable in a cocoa objective-c class work?
I've seen in a few iPhone examples that attributes have used an underscore _ in front of the variable. Does anyone know what this means? Or how it works?
...
Best way to serialize an NSData into a hexadeximal string
...rsion.h
#import <Foundation/Foundation.h>
@interface NSData (NSData_Conversion)
#pragma mark - String Conversion
- (NSString *)hexadecimalString;
@end
NSData+Conversion.m
#import "NSData+Conversion.h"
@implementation NSData (NSData_Conversion)
#pragma mark - String Conversion
- (NSStr...
Where can I learn how to write C code to speed up slow R functions? [closed]
...:
SEXP foobar(){
SEXP ab;
PROTECT(ab = allocVector(STRSXP, 2));
SET_STRING_ELT( ab, 0, mkChar("foo") );
SET_STRING_ELT( ab, 1, mkChar("bar") );
UNPROTECT(1);
}
Using Rcpp, you can write the same function as:
SEXP foobar(){
return Rcpp::CharacterVector::create( "foo", "bar" ) ;
}
...
When to use self over $this?
...on-static and static member variables:
<?php
class X {
private $non_static_member = 1;
private static $static_member = 2;
function __construct() {
echo $this->non_static_member . ' '
. self::$static_member;
}
}
new X();
?>
Here is an example of incorr...
How to convert boost path type to string?
... canonical is deprecated in newer versions of Boost boost.org/doc/libs/1_48_0/libs/filesystem/v3/doc/…
– Brian Jack
Nov 30 '14 at 2:59
...
Is gettimeofday() guaranteed to be of microsecond resolution?
...fectively makes the answer to your question no.
You should look into clock_gettime(CLOCK_MONOTONIC) for timing intervals. It suffers from several less issues due to things like multi-core systems and external clock settings.
Also, look into the clock_getres() function.
...
Best way to test if a row exists in a MySQL table
...ng':
SELECT * FROM test WHERE texte LIKE '%something%' LIMIT 1 with
mysql_num_rows() : 0.039061069488525s. (FASTER)
SELECT count(*) as count FROM test WHERE text LIKE '%something% :
16.028197050095s.
SELECT EXISTS(SELECT 1 FROM test WHERE text LIKE '%something%') :
0.87045907974243s.
SELECT EXIS...
Django FileField with upload_to determined at runtime
...ng to set up my uploads so that if user joe uploads a file it goes to MEDIA_ROOT/joe as opposed to having everyone's files go to MEDIA_ROOT. The problem is I don't know how to define this in the model. Here is how it currently looks:
...
Rails 2.3-style plugins and deprecation warnings running task in Heroku
...x applications ..
To avoid this
injection in Rails 3, include the rails_12factor gem in your
application. (Heroku Ruby Support 2013-10-26)
The rails_12factor gem is also required in rails 4.
If this gem is not present in your application, you will receive a
warning while deploying, and...