大约有 12,000 项符合查询结果（耗时：0.0326秒） [XML]
Hashing a dictionary?
... However, here is one issue I found with hash, as regards objects:
class Foo(object): pass
foo = Foo()
print (hash(foo)) # 1209812346789
foo.a = 1
print (hash(foo)) # 1209812346789
The hash is the same, even after I've altered foo. This is because the identity of foo hasn't changed, so the hash...
StringUtils.isBlank() vs String.isEmpty()
...
StringUtils.isBlank() will also check for null, whereas this:
String foo = getvalue("foo");
if (foo.isEmpty())
will throw a NullPointerException if foo is null.
share
|
improve this answer
...
What is the difference between 'E', 'T', and '?' for Java generics?
... wildcard which is used when providing a type argument, e.g. List<?> foo = ... means that foo refers to a list of some type, but we don't know what.
All of this is generics, which is a pretty huge topic. You may wish to learn about it through the following resources, although there are more a...
How to filter rows in pandas by regex
...lready a string handling function Series.str.startswith().
You should try foo[foo.b.str.startswith('f')].
Result:
a b
1 2 foo
2 3 fat
I think what you expect.
Alternatively you can use contains with regex option. For example:
foo[foo.b.str.contains('oo', regex= True, na=False)...
What does 'const static' mean in C and C++?
...n other forums. My best guess is that it's used in C to hide the constant foo from other modules. Is this correct? If so, why would anyone use it in a C++ context where you can just make it private ?
...
Jasmine JavaScript Testing - toBe vs toEqual
...nd toEqual, let's imagine three objects.
var a = { bar: 'baz' },
b = { foo: a },
c = { foo: a };
Using a strict comparison (===), some things are "the same":
> b.foo.bar === c.foo.bar
true
> b.foo.bar === a.bar
true
> c.foo === b.foo
true
But some things, even though they are "e...
How can I get a list of all classes within current module in Python?
...per' way to do it, but your snippet is on the right track: just add import foo to foo.py, do inspect.getmembers(foo), and it should work fine.
share
|
improve this answer
|
f...
Undefined reference to static class member
...he static member somewhere (after the class definition). Try this:
class Foo { /* ... */ };
const int Foo::MEMBER;
int main() { /* ... */ }
That should get rid of the undefined reference.
share
|
...
Why use the 'ref' keyword when passing an object?
...nt to change what the object is:
TestRef t = new TestRef();
t.Something = "Foo";
DoSomething(ref t);
void DoSomething(ref TestRef t)
{
t = new TestRef();
t.Something = "Not just a changed t, but a completely different TestRef object";
}
After calling DoSomething, t does not refer to the origin...
Normal arguments vs. keyword arguments
... where the distinction is important. Consider the following function:
def foo(*positional, **keywords):
print "Positional:", positional
print "Keywords:", keywords
The *positional argument will store all of the positional arguments passed to foo(), with no limit to how many you can provid...