大约有 13,700 项符合查询结果（耗时：0.0430秒） [XML]
sqlalchemy: how to join several tables by one query?
...integer primary keys for everything, but whatever):
class User(Base):
__tablename__ = 'users'
email = Column(String, primary_key=True)
name = Column(String)
class Document(Base):
__tablename__ = "documents"
name = Column(String, primary_key=True)
author_email = Column(Strin...
Does C++ support 'finally' blocks? (And what's this 'RAII' I keep hearing about?)
...ing a mutex:
// A class with implements RAII
class lock
{
mutex &m_;
public:
lock(mutex &m)
: m_(m)
{
m.acquire();
}
~lock()
{
m_.release();
}
};
// A class which uses 'mutex' and 'lock' objects
class foo
{
mutex mutex_; // mutex for l...
Project structure for Google App Engine
... had trouble with packages. Just make sure each of your sub folders has an __init__.py file. It's ok if its empty.
Boilerplate files
These hardly vary between projects
app.yaml: direct all non-static requests to main.py
main.py: initialize app and send it all requests
Project lay-out
static...
Javascript regex returning true.. then false.. then true.. etc [duplicate]
...
/^[^-_]([a-z0-9-_]{4,20})[^-_]$/gi;
You're using a g (global) RegExp. In JavaScript, global regexen have state: you call them (with exec, test etc.) the first time, you get the first match in a given string. Call them again and ...
Which characters are valid in CSS class names/selectors?
...tly at the CSS grammar.
Basically1, a name must begin with an underscore (_), a hyphen (-), or a letter(a–z), followed by any number of hyphens, underscores, letters, or numbers. There is a catch: if the first character is a hyphen, the second character must2 be a letter or underscore, and the n...
Get name of object or class
... use standard IIFE (for example with TypeScript)
var Zamboch;
(function (_Zamboch) {
(function (Web) {
(function (Common) {
var App = (function () {
function App() {
}
App.prototype.hello = function () {
co...
How to print a dictionary line by line in Python?
...
I do print(json.dumps(cars, indent=4, ensure_ascii=False)) because otherwise non-ASCII characters are unreadable.
– Boris
Apr 22 at 16:36
add a ...
How do I create a copy of an object in PHP?
...an be seen from this example: $a = new stdClass; $b =& $a; $a = 42; var_export($b); here $b is a reference to the variable $a; if you replace =& with a normal =, it is not a reference, and still points to the original object.
– IMSoP
Jun 16 '13 at 21:14...
What's the difference between using CGFloat and float?
...undation source code, in CoreGraphics' CGBase.h:
/* Definition of `CGFLOAT_TYPE', `CGFLOAT_IS_DOUBLE', `CGFLOAT_MIN', and
`CGFLOAT_MAX'. */
#if defined(__LP64__) && __LP64__
# define CGFLOAT_TYPE double
# define CGFLOAT_IS_DOUBLE 1
# define CGFLOAT_MIN DBL_MIN
# define CGFLOAT_MAX DBL_M...
How to write inline if statement for print?
... condition:
block
if expression (introduced in Python 2.5)
expression_if_true if condition else expression_if_false
And note, that both print a and b = a are statements. Only the a part is an expression. So if you write
print a if b else 0
it means
print (a if b else 0)
and similarly ...