大约有 6,261 项符合查询结果（耗时：0.0169秒） [XML]
How does the “final” keyword in Java work? (I can still modify an object.)
...
try to do t.foo = new ArrayList(); in the main method and you will get compilation error...the reference foo is binded to just one final object of ArrayList...it cannot point to any other ArrayList
– Code2Interface
...
How to test if list element exists?
...ome effort) contain NULL elements, it might not be enough to check is.null(foo$a). A more stringent test might be to check that the name is actually defined in the list:
foo <- list(a=42, b=NULL)
foo
is.null(foo[["a"]]) # FALSE
is.null(foo[["b"]]) # TRUE, but the element "exists"...
is.null(foo...
How to use sed to replace only the first occurrence in a file?
...
# sed script to change "foo" to "bar" only on the first occurrence
1{x;s/^/first/;x;}
1,/foo/{x;/first/s///;x;s/foo/bar/;}
#---end of script---
or, if you prefer: Editor's note: works with GNU sed only.
sed '0,/foo/s//bar/' file
Source
...
C++静态和多态，亦敌亦友 - C/C++ - 清泛网 - 专注C/C++及内核技术
...ostream>
using namespace std;
class Base
{
public:
virtual void foo(void){ cout << "Base::foo()" << endl; }
};
class Derived : public Base
{
public:
void foo(void){ cout << "Derived::foo()" << endl; }
} ;
class DerivedAgain : public Derived
{
public:
static void foo(...
Difference between staticmethod and classmethod
...of example code will help: Notice the difference in the call signatures of foo, class_foo and static_foo:
class A(object):
def foo(self, x):
print "executing foo(%s, %s)" % (self, x)
@classmethod
def class_foo(cls, x):
print "executing class_foo(%s, %s)" % (cls, x)
...
Difference between 'struct' and 'typedef struct' in C++?
...entifiers (for typedef and other identifiers).
If you just said:
struct Foo { ... };
Foo x;
you would get a compiler error, because Foo is only defined in the tag namespace.
You'd have to declare it as:
struct Foo x;
Any time you want to refer to a Foo, you'd always have to call it a struc...
Converting a Java Keystore into PEM Format
... pretty straightforward, using jdk6 at least...
bash$ keytool -keystore foo.jks -genkeypair -alias foo \
-dname 'CN=foo.example.com,L=Melbourne,ST=Victoria,C=AU'
Enter keystore password:
Re-enter new password:
Enter key password for
(RETURN if same as keystore password):
bas...
Storing C++ template function definitions in a .CPP file
...its the following...
In your .h file...
template<typename T>
class foo
{
public:
void bar(const T &t);
};
And in your .cpp file
template <class T>
void foo<T>::bar(const T &t)
{ }
// Explicit template instantiation
template class foo<int>;
...
What does “var FOO = FOO || {}” (assign a variable or an empty object to that variable) mean in Java
...tional arguments and initialize them to defaults if not provided: function foo(arg1, optarg1, optarg2) { optarg1 = optarg1 || 'default value 1'; optarg2 = optart2 || 'defalt value 2';}
– crazy2be
Jun 22 '11 at 19:24
...
Makefile经典教程（入门必备） - C/C++ - 清泛网 - 专注IT技能提升
...，你有这样几个Makefile：a.mk、b.mk、c.mk，还有一个文件叫foo.make，以及一个变量$(bar)，其包含了e.mk和f.mk，那么，下面的语句：
2.如果目录/include（一般是：/usr/local/bin或/usr/include）存在的话，make也会去找。
...