大约有 40,000 项符合查询结果（耗时：0.0320秒） [XML]
What are good uses for Python3's “Function Annotations”
...re what you make of them.
They can be used for documentation:
def kinetic_energy(mass: 'in kilograms', velocity: 'in meters per second'):
...
They can be used for pre-condition checking:
def validate(func, locals):
for var, test in func.__annotations__.items():
value = locals[v...
How does Django's Meta class work?
...n [2]: User.Meta
Out[2]: django.contrib.auth.models.Meta
In [3]: User.Meta.__dict__
Out[3]:
{'__doc__': None,
'__module__': 'django.contrib.auth.models',
'abstract': False,
'verbose_name': <django.utils.functional.__proxy__ at 0x26a6610>,
'verbose_name_plural': <django.utils.functional...
What does extern inline do?
... I'd like to add that for Microsoft's Visual C++, there's a __forceinline keyword that will enforce your function getting inlined. This is obviously a compiler-specific extension only for VC++.
– untitled8468927
Jan 17 '14 at 12:12
...
sqlalchemy unique across multiple columns
... declares those in the table definition, or if using declarative as in the __table_args__:
# version1: table definition
mytable = Table('mytable', meta,
# ...
Column('customer_id', Integer, ForeignKey('customers.customer_id')),
Column('location_code', Unicode(10)),
UniqueConstraint...
What is the best way to compute trending topics or tags?
...wing code demonstrates this.
from math import sqrt
class zscore:
def __init__(self, pop = []):
self.number = float(len(pop))
self.total = sum(pop)
self.sqrTotal = sum(x ** 2 for x in pop)
def update(self, value):
self.number += 1.0
self.total += valu...
In Python, how do I indicate I'm overriding a method?
...an think of a better solution please post it here!
def overrides(interface_class):
def overrider(method):
assert(method.__name__ in dir(interface_class))
return method
return overrider
It works as follows:
class MySuperInterface(object):
def my_method(self):
p...
Re-raise exception with a different type and message, preserving existing information
...ble to whatever code catches the new exception.
By using this feature, the __cause__ attribute is set. The built-in exception handler also knows how to report the exception's “cause” and “context” along with the traceback.
In Python 2, it appears this use case has no good answer (as describ...
Why is `std::move` named `std::move`?
...
template <class T>
void
swap(T& a, T& b)
{
T tmp(static_cast<T&&>(a));
a = static_cast<T&&>(b);
b = static_cast<T&&>(tmp);
}
One has to recall that at this point in history, the only thing that "&&" could possibly mean w...
Bulk insert with SQLAlchemy ORM
... = [
User(name="u1"),
User(name="u2"),
User(name="u3")
]
s.bulk_save_objects(objects)
s.commit()
Here, a bulk insert will be made.
share
|
improve this answer
|
...
Case insensitive 'in'
...ive. Minimally, for example...:
class CaseInsensitively(object):
def __init__(self, s):
self.__s = s.lower()
def __hash__(self):
return hash(self.__s)
def __eq__(self, other):
# ensure proper comparison between instances of this class
try:
oth...