大约有 40,000 项符合查询结果（耗时：0.0690秒） [XML]
MongoDB relationships: embed or reference?
I'm new to MongoDB--coming from a relational database background. I want to design a question structure with some comments, but I don't know which relationship to use for comments: embed or reference ?
...
Batch file to copy files from one folder to another folder
...heir active data on a server. Now that server is going to be replaced by a new one due to place problem so I need to copy sub folders files from the old server storage folder to new server storage folder. I have below ex:
...
Java null check why use == instead of .equals()
... /* In a real class, you'd override `hashCode` here as well */
}
Foo f1 = new Foo(5);
Foo f2 = new Foo(5);
System.out.println(f1 == f2);
// outputs false, they're distinct object instances
System.out.println(f1.equals(f2));
// outputs true, they're "equal" according to their definition
Foo f3 = n...
GroupBy pandas DataFrame and select most common value
...{'Country' : ['USA', 'USA', 'Russia','USA'],
'City' : ['New-York', 'New-York', 'Sankt-Petersburg', 'New-York'],
'Short name' : ['NY','New','Spb','NY']})
source.groupby(['Country','City']).agg(lambda x:x.value_counts().index[0])
In case you are wondering about ...
python: how to send mail with TO, CC and BCC?
...
As of Python 3.2, released Nov 2011, the smtplib has a new function send_message instead of just sendmail, which makes dealing with To/CC/BCC easier. Pulling from the Python official email examples, with some slight modifications, we get:
# Import smtplib for the actual sending ...
Why main does not return 0 here?
...unction () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f8677672%2fwhy-main-does-not-return-0-here%23new-answer', 'question_page');
}
);
...
What are the differences between Clojure, Scheme/Racket and Common Lisp?
...arbitrary code at runtime (often used to either "extend the language" with new syntax or create DSLs)
Often used in functional programming style, although have the ability to accommodate other paradigms
Emphasis in interactive development with a REPL (i.e. you interactively develop in a running inst...
Canvas width and height in HTML5
Is it possible to fix the width and height of an HTML5 canvas element?
4 Answers
4
...
Why doesn't java.lang.Number implement Comparable? [duplicate]
...
It's worth mentioning that the following expression:
new Long(10).equals(new Integer(10))
is always false, which tends to trip everyone up at some point or another. So not only can you not compare arbitrary Numbers but you can't even determine if they're equal or not.
Also,...
ASP.NET Identity's default Password Hasher - How does it work and is it secure?
...[] salt;
byte[] buffer2;
if (password == null)
{
throw new ArgumentNullException("password");
}
using (Rfc2898DeriveBytes bytes = new Rfc2898DeriveBytes(password, 0x10, 0x3e8))
{
salt = bytes.Salt;
buffer2 = bytes.GetBytes(0x20);
}
byte[] dst =...