大约有 44,000 项符合查询结果（耗时：0.0575秒） [XML]
How should I have explained the difference between an Interface and an Abstract class?
...implementation of this only:
public abstract void checkDBforUser();
}
Now in each child class, we only need to implement one method - the method that is database dependent.
share
|
improve thi...
How can I create directories recursively? [duplicate]
...
I agree with Cat Plus Plus's answer. However, if you know this will only be used on Unix-like OSes, you can use external calls to the shell commands mkdir, chmod, and chown. Make sure to pass extra flags to recursively affect directories:
>>> import subprocess
>>...
Why is using the rails default_scope often recommend against?
...WHERE "posts"."published" = 't'
Well this is pretty much what we expect. Now lets try:
2.1.1 :004 > Post.new
=> #<Post id: nil, title: nil, published: true, created_at: nil, updated_at: nil>
And there we have the first big problem with default scope:
=> default_scope will aff...
What is a 'semantic predicate' in ANTLR?
... instead of a parser rule) that will match numbers in the range of 0..999. Now in the parser, you'd like to make a distinction between low- and hight numbers (low: 0..500, high: 501..999). This could be done using a disambiguating semantic predicate where you inspect the token next in the stream (in...
How do you find out the type of an object (in Swift)?
...es, it's useful to be able to actually find out what type something is. I know the debugger can show you some type information, and you can usually rely on type inference to get away with not specifying the type in those situations, but still, I'd really like to have something like Python's type()
...
applicationWillEnterForeground vs. applicationDidBecomeActive, applicationWillResignActive vs. appli
...
Revise some descriptions and links, 2019 for now.
– tomjpsun
Sep 20 '19 at 2:56
add a comment
|
...
For i = 0, why is (i += i++) equal to 0?
...ough decomposition of i += i++ to the parts it is made of requires one to know that both += and ++ are not atomic (that is, neither one is a single operation), even if they look like they are. The way these are implemented involve temporary variables, copies of i before the operations take place - o...
Relation between CommonJS, AMD and RequireJS?
...
FYI Browserify will now let you use CommonJS in the browser.
– Eruant
Jan 30 '14 at 12:03
9
...
SVN: Ignore some directories recursively
...
As of subversion 1.8, there is now the svn:global-ignores property which works like svn:ignore but recursively (so set this on your top-level directory)
share
|
...
outline on only one border
...nset border into an HTML element, but just only on one side of it.
Until now, I've been using an image to do that (GIF/PNG) that I would then use as a background and stretch it (repeat-x) and position a little off from the top of my block.
Recently, I discovered the outline CSS property, which i...