大约有 20,000 项符合查询结果（耗时：0.0420秒） [XML]
html select option separator
...on>First</option>
</optgroup>
<optgroup label="_________">
<option>Second</option>
<option>Third</option>
</optgroup>
</select>
disabled option (a bit better):
<select>
<option>Fir...
How to convert list of tuples to multiple lists?
...
xs, ys = [x for x, y in zs], [y for x, y in zs]
return xs, ys
if __name__ == '__main__':
from timeit import timeit
setup_string='''\
N = 2000000
xs = list(range(1, N))
ys = list(range(N+1, N*2))
zs = list(zip(xs, ys))
from __main__ import t1, t2, t3
'''
print(f'zip:\t\t{timeit(...
Does MySQL index foreign key columns automatically?
... where the foreign key columns are listed as the first columns in the same order. Such an index is created on the referencing table automatically if it does not exist. (This is in contrast to some older versions, in which indexes had to be created explicitly or the creation of foreign key constraint...
The SMTP server requires a secure connection or the client was not authenticated. The server respons
....Credentials after calling SmtpClient.UseDefaultCredentials = false.
The order is important as setting SmtpClient.UseDefaultCredentials = false will reset SmtpClient.Credentials to null.
share
|
i...
decorators in the python standard lib (@deprecated specifically)
...ed
when the function is used."""
@functools.wraps(func)
def new_func(*args, **kwargs):
warnings.simplefilter('always', DeprecationWarning) # turn off filter
warnings.warn("Call to deprecated function {}.".format(func.__name__),
category=DeprecationW...
Get ID of last inserted document in a mongoDB w/ Java driver
...me", "Matt" );
collection.insert( doc );
ObjectId id = (ObjectId)doc.get( "_id" );
share
|
improve this answer
|
follow
|
...
When to use a key/value store such as Redis instead/along side of a SQL database?
...ngle threaded and so forth. I think that another big difference is that in order to take advantage of Redis in your production environment you don't need to switch to Redis. You can just use it in order to do new things that were not possible before, or in order to fix old problems.
Use cases the ...
if A vs if A is not None:
...
The statement
if A:
will call A.__nonzero__() (see Special method names documentation) and use the return value of that function. Here's the summary:
object.__nonzero__(self)
Called to implement truth value testing and the built-in operation bool()...
Access nested dictionary items via a list of keys?
..., 'z': 3}, 'w': 3}}
Note that the Python PEP8 style guide prescribes snake_case names for functions. The above works equally well for lists or a mix of dictionaries and lists, so the names should really be get_by_path() and set_by_path():
from functools import reduce # forward compatibility for Py...
The tilde operator in Python
...s operator.invert. To support this operator in your own class, give it an __invert__(self) method.
>>> import operator
>>> class Foo:
... def __invert__(self):
... print 'invert'
...
>>> x = Foo()
>>> operator.invert(x)
invert
>>> ~x
invert
Any ...