大约有 40,000 项符合查询结果（耗时：0.0466秒） [XML]
Determine what attributes were changed in Rails after_save callback?
I'm setting up an after_save callback in my model observer to send a notification only if the model's published attribute was changed from false to true. Since methods such as changed? are only useful before the model is saved, the way I'm currently (and unsuccessfully) trying to do so is as fol...
LINQ - Full Outer Join
...
I don't know if this covers all cases, logically it seems correct. The idea is to take a left outer join and right outer join then take the union of the results.
var firstNames = new[]
{
new { ID = 1, Name = "John" },
new { ID = 2, Name = "Sue"...
How do I pass a method as a parameter in Python
...thodToRun()
return result
obj.method2(obj.method1)
Note: I believe a __call__() method does exist, i.e. you could technically do methodToRun.__call__(), but you probably should never do so explicitly. __call__() is meant to be implemented, not to be invoked from your own code.
If you wanted me...
How do I print a double value with full precision using cout?
...
Is the really the right answer? When I manually use a high number, I can print out as many as 51 digits of approximated e, but with cout.precision(numeric_limits<double>::digits10 + 2); I only get 16....
– ...
Why is early return slower than else?
...e a theory for you.
I tried your code and get the same of results, without_else() is repeatedly slightly slower than with_else():
>>> T(lambda : without_else()).repeat()
[0.42015745017874906, 0.3188967452567226, 0.31984281521812363]
>>> T(lambda : with_else()).repeat()
[0.3600984...
Class vs. static method in JavaScript
... instantiate an object from that function using the new keyword which will allow you to create something similar to a class in a standard OOP language.
I'd suggest ignoring __proto__ most of the time because it has poor cross browser support, and instead focus on learning about how prototype works....
serve current directory from command line
...also running on a Mac. Tried it with Ruby 1.8.7, 1.9.3 and 2.0.0, and they all work. Weird.
– Daniel Perez Alvarez
Sep 9 '13 at 9:04
7
...
Vim: Replacing a line with another one yanked before
... If you overwrite additional lines with ccCTRL+r0ESC instead of V"0p then all following lines can be replaced with just . (the repeater)
– Jordan Morris
Aug 26 '13 at 5:10
...
Merge Images Side by Side(Horizontally)
...hips with the montage utility. Montage will append each image side-by-side allowing you to adjust spacing between each image (-geometry), and the general layout (-tile).
montage [0-5].png -tile 5x1 -geometry +0+0 out.png
Other examples can be found on Montage Usage page
...
Using OR in SQLAlchemy
...
From the tutorial:
from sqlalchemy import or_
filter(or_(User.name == 'ed', User.name == 'wendy'))
share
|
improve this answer
|
follow
...