大约有 12,000 项符合查询结果（耗时：0.0361秒） [XML]
How to have the cp command create any necessary folders for copying a file to a destination [duplica
... only reliable way to do this would be to combine mkdir and cp:
mkdir -p /foo/bar && cp myfile "$_"
As an aside, when you only need to create a single directory in an existing hierarchy, rsync can do it in one operation. I'm quite a fan of rsync as a much more versatile cp replacement, i...
What is your most productive shortcut with Vim?
...s they can also be used as "subjects" in our "statements." So I can use d/foo to cut from the current line to the next line containing the string "foo" and y?bar to copy from the current line to the most recent (previous) line containing "bar." If I don't want whole lines I can still use the searc...
Copy constructor for a class with unique_ptr
.../some stuff
};
struct Derived : public Base
{
//some stuff
};
struct Foo
{
std::unique_ptr<Base> ptr; //points to Derived or some other derived class
};
... and the goal is, as said, to make Foo copiable.
For this, one needs to do a deep copy of the contained pointer to ensure th...
When should I use “this” in a class?
...lue of the parameter "name" to the instance variable "name".
public class Foo
{
private String name;
public void setName(String name) {
this.name = name;
}
}
Case 2: Using this as an argument passed to another object.
public class Foo
{
public String useBarMethod() {
...
How to get the list of properties of a class?
...on; for an instance:
obj.GetType().GetProperties();
for a type:
typeof(Foo).GetProperties();
for example:
class Foo {
public int A {get;set;}
public string B {get;set;}
}
...
Foo foo = new Foo {A = 1, B = "abc"};
foreach(var prop in foo.GetType().GetProperties()) {
Console.WriteLi...
jQuery object equality
... you can use .is. Below is the answer from over a year ago...
var a = $('#foo');
var b = a;
if (a.is(b)) {
// the same object!
}
If you want to see if two variables are actually the same object, eg:
var a = $('#foo');
var b = a;
...then you can check their unique IDs. Every time you cr...
Why do we need extern “C”{ #include } in C++?
...ll use C++ name mangling. Here's an example.
Given test.C like so:
void foo() { }
Compiling and listing symbols in the object file gives:
$ g++ -c test.C
$ nm test.o
0000000000000000 T _Z3foov
U __gxx_personality_v0
The foo function is actually called "_Z3foov". This string...
Nullable type issue with ?: Conditional Operator
...know how convert null into a DateTime.
The solution is simple:
DateTime? foo;
foo = true ? (DateTime?)null : new DateTime(0);
Note that Nullable<DateTime> can be written DateTime? which will save you a bunch of typing.
...
Passing a list of kwargs?
...like this:
def method(**kwargs):
print kwargs
keywords = {'keyword1': 'foo', 'keyword2': 'bar'}
method(keyword1='foo', keyword2='bar')
method(**keywords)
Running this in Python confirms these produce identical results:
{'keyword2': 'bar', 'keyword1': 'foo'}
{'keyword2': 'bar', 'keyword1': 'fo...
How to check whether a Storage item is set?
...ou can use hasOwnProperty method to check this
> localStorage.setItem('foo', 123)
undefined
> localStorage.hasOwnProperty('foo')
true
> localStorage.hasOwnProperty('bar')
false
Works in current versions of Chrome(Mac), Firefox(Mac) and Safari.
...