大约有 44,000 项符合查询结果（耗时：0.2123秒） [XML]
Unicode equivalents for \w and \b in Java regular expressions?
...e as an embeddable (?U) for inside the pattern, so you can use it with the String class’s wrappers, too. It also sports corrected definitions for various other properties, too. It now tracks The Unicode Standard, in both RL1.2 and RL1.2a from UTS#18: Unicode Regular Expressions. This is an excit...
Forking vs. Branching in GitHub
...ith a fork.
The merge experience would be about the same, but with an extra level of indirection (push first on the fork, then ask for a pull, with the risk of evolutions on the original repo making your fast-forward merges not fast-forward anymore).
That means the correct workflow is to git pu...
What is the difference between a 'closure' and a 'lambda'?
...l these free symbols by binding them to some values (which may be numbers, strings, anonymous functions aka lambdas, whatever…).
And here comes the closure part:
The closure of a lambda expression is this particular set of symbols defined in the outer context (environment) that give values to the...
iPhone - Grand Central Dispatch main thread
...rocessing has finished e.g.
- (void)doCalculation
{
//you can use any string instead "com.mycompany.myqueue"
dispatch_queue_t backgroundQueue = dispatch_queue_create("com.mycompany.myqueue", 0);
dispatch_async(backgroundQueue, ^{
int result = <some really long calculation th...
How does having a dynamic variable affect performance?
...method we call were trying to do something intensive, like combining a few strings together or searching a collection for a value, those operations would likely far outweigh the difference between a direct call and a dynamic call.
Performance is just one of many good reasons not to use dynamic unnec...
What does “fragment” mean in ANTLR?
...lly they'll improve readability of your grammars.
look at this example :
STRING : '"' (ESC | ~["\\])* '"' ;
fragment ESC : '\\' (["\\/bfnrt] | UNICODE) ;
fragment UNICODE : 'u' HEX HEX HEX HEX ;
fragment HEX : [0-9a-fA-F] ;
STRING is a lexer using fragment rule like ESC .Unicode is used in Esc r...
JavaScript ternary operator example with functions
...nch, you have a muti-branched if/else tree, or multiple else/ifs in a long string.
The ternary operator is common when you're assigning a value to a variable based on a simple condition or you are making multiple decisions with very brief outcomes. The example you cite actually doesn't make sense,...
What is the most efficient/elegant way to parse a flat table into a tree?
... sets (sometimes referred to as Modified Pre-order Tree Traversal) you can extract the entire tree structure or any subtree within it in tree order with a single query, at the cost of inserts being more expensive, as you need to manage columns which describe an in-order path through thee tree struct...
How to pass objects to functions in C++?
... C tmp = a;
a = b;
b = tmp;
}
public static void main( String args[] ) {
C a = new C();
C b = new C();
C old_a = a;
C old_b = b;
swap( a, b );
// a and b remain unchanged a==old_a, and b==old_b
}
}
The Java version of the code will modify...
What's the purpose of using braces (i.e. {}) for a single-line if or loop?
...d) (b*b) - ((4*a)*c)?
Some precedences are obvious (or should be), and the extra parentheses
just add to confusion. (On the other hand, you _should_ use the
parentheses in less obvious cases, even if you know that they're not
needed.)
Sort of. There are two wide spread conventions for formatting...