大约有 16,000 项符合查询结果（耗时：0.0327秒） [XML]
Use of def, val, and var in scala
... Person) you are changing the age member variable.
And the last line:
println(person.age)
Here you are again calling the person method, which returns a new instance of class Person (with age set to 12). It's the same as this:
println(person().age)
...
Tab key == 4 spaces and auto-indent after curly braces in Vim
How do I make vi - Vim never use tabs (converting spaces to tabs, bad!), makes the tab key == 4 spaces, and automatically indent code after curly brace blocks like Emacs does?
...
Check if UIColor is dark or bright?
...l? {
let originalCGColor = self.cgColor
// Now we need to convert it to the RGB colorspace. UIColor.white / UIColor.black are greyscale and not RGB.
// If you don't do this then you will crash when accessing components index 2 below when evaluating greyscale colors.
...
How to remove certain characters from a string in C++?
... string str("(555) 555-5555");
char chars[] = "()-";
for (unsigned int i = 0; i < strlen(chars); ++i)
{
// you need include <algorithm> to use general algorithms like std::remove()
str.erase (std::remove(str.begin(), str.end(), chars[i]), str.end());
}
// outpu...
Modern way to filter STL container?
...
See the example from cplusplus.com for std::copy_if:
std::vector<int> foo = {25,15,5,-5,-15};
std::vector<int> bar;
// copy only positive numbers:
std::copy_if (foo.begin(), foo.end(), std::back_inserter(bar), [](int i){return i>=0;} );
std::copy_if evaluates the lambda expr...
What exactly is LLVM?
...u provide the "front end" (parser and lexer) and the "back end" (code that converts LLVM's representation to actual machine code).
LLVM can also act as a JIT compiler - it has support for x86/x86_64 and PPC/PPC64 assembly generation with fast code optimizations aimed for compilation speed.
Unfortu...
KeyValuePair VS DictionaryEntry
...n Chris' example (in which we have two dictionaries containing <string, int> pairs).
Dictionary<string, int> dict = new Dictionary<string, int>();
foreach (KeyValuePair<string, int> item in dict) {
int i = item.Value;
}
Hashtable hashtable = new Hashtable();
foreach (Dict...
How do you implement a re-try-catch?
...
You need to enclose your try-catch inside a while loop like this: -
int count = 0;
int maxTries = 3;
while(true) {
try {
// Some Code
// break out of loop, or return, on success
} catch (SomeException e) {
// handle exception
if (++count == maxTries) th...
What is the most efficient way of finding all the factors of a number in Python?
...urn set(reduce(list.__add__,
([i, n//i] for i in range(1, int(n**0.5) + 1) if n % i == 0)))
This will return all of the factors, very quickly, of a number n.
Why square root as the upper limit?
sqrt(x) * sqrt(x) = x. So if the two factors are the same, they're both the square ro...
What is the formal difference in Scala between braces and parentheses, and when should they be used?
...t is best to concentrate on where curly braces and parenthesis can be used interchangeably: when passing parameters to method calls. You may replace parenthesis with curly braces if, and only if, the method expects a single parameter. For example:
List(1, 2, 3).reduceLeft{_ + _} // valid, single Fun...