大约有 49,000 项符合查询结果（耗时：0.0379秒） [XML]
mongodb: insert if not exists
... This is almost what I want ! How can I not touch the insertion_date field if the object is already present ?
– LeMiz
May 27 '10 at 21:24
28
...
multiple prints on the same line in Python
... can use the print statement to do this without importing sys.
def install_xxx():
print "Installing XXX... ",
install_xxx()
print "[DONE]"
The comma on the end of the print line prevents print from issuing a new line (you should note that there will be an extra space at the end of the ou...
More elegant way of declaring multiple variables at the same time
...ension, but here's a very readable implementation:
>>> def invert_dict(inverted_dict):
... elements = inverted_dict.iteritems()
... for flag_value, flag_names in elements:
... for flag_name in flag_names:
... yield flag_name, flag_value
...
>>> flags =...
Pros and Cons of Interface constants [closed]
...mple of a good enough and a bad use:
Bad:
interface User {
const TYPE_ADMINISTRATOR = 1;
const TYPE_USER = 2;
const TYPE_GUEST = 3;
}
Good Enough:
interface HTTPRequest_1_1 {
const TYPE_CONNECT = 'connect';
const TYPE_DELETE = 'delete';
const TYPE_GET ...
App Inventor 2 手势识别扩展教程 - GestureDetector · App Inventor 2 中文网
...
when GestureDetector1.DoubleTapAtPoint(X, Y) {
// 双击触发
标签_状态.Text = join("双击 @ ", X, ",", Y)
}
when GestureDetector1.LongClick(X, Y) {
// 长按触发
标签_状态.Text = join("长按 @ ", X, ",", Y)
}
when GestureDetector1.ThumbEnabled(起点X, 起点Y, 终点X, 终...
Using an image caption in Markdown Jekyll
... generating the site first), you can create a new file named image.html in _includes:
<figure class="image">
<img src="{{ include.url }}" alt="{{ include.description }}">
<figcaption>{{ include.description }}</figcaption>
</figure>
And then display the image from...
How do I set bold and italic on UILabel of iPhone/iPad?
...t {
return with([.traitBold, .traitItalic])
}
func with(_ traits: UIFontDescriptor.SymbolicTraits...) -> UIFont {
guard let descriptor = self.fontDescriptor.withSymbolicTraits(UIFontDescriptor.SymbolicTraits(traits).union(self.fontDescriptor.symbolicTraits)) else {
...
What is the 'override' keyword in C++ used for? [duplicate]
... : base
{
virtual void foo() override
{
std::cout << __PRETTY_FUNCTION__ << std::endl;
}
};
int main()
{
base* override = new derived();
override->foo();
return 0;
}
Output:
zaufi@gentop /work/tests $ g++ -std=c++11 -o override-test override-test.cc...
How do I append one string to another in Python?
...O(n^2), but now it is O(n).
From the source (bytesobject.c):
void
PyBytes_ConcatAndDel(register PyObject **pv, register PyObject *w)
{
PyBytes_Concat(pv, w);
Py_XDECREF(w);
}
/* The following function breaks the notion that strings are immutable:
it changes the size of a string. We g...
How to check if click event is already bound - JQuery
...this bug for details.) It is possible to access the same data with jQuery._data(elem, 'events'), an internal data structure, which is undocumented and therefore not 100% guaranteed to remain stable. This shouldn't, however, be a problem, and the relevant line of the plugin code above can be change...