大约有 40,000 项符合查询结果（耗时：0.0550秒） [XML]
How to create composite primary key in SQL Server 2008
...
create table my_table (
column_a integer not null,
column_b integer not null,
column_c varchar(50),
primary key (column_a, column_b)
);
share
...
Explain how finding cycle start node in cycle linked list work?
... @Passionate: Take mu steps from the start point to get to X_mu, the start of the cycle (by definition of mu). Then if you take i more steps, where i is a multiple of the cycle length, you end up back at the cycle start: X_mu + i = X_mu. But addition is commutative, so this is equiva...
Using comparison operators in Scala's pattern matching system
...("ten")
case x if x > 10 => println("greater than ten")
case _ => println("less than ten")
}
Edit: Note that this is more than superficially different to putting an if after the =>, because a pattern won't match if the guard is not true.
...
Why are dashes preferred for CSS selectors / HTML attributes?
...ument.querySelector('#first-name');
var firstName = document.forms[0].first_name;
I find the two first options much more preferable, especially since '#first-name' can be replaced with a JavaScript variable and built dynamically. I also find them more pleasant on the eyes.
The fact that Sass enab...
Creating a zero-filled pandas data frame
... try this:
d = pd.DataFrame(0, index=np.arange(len(data)), columns=feature_list)
share
|
improve this answer
|
follow
|
...
How do you represent a JSON array of strings?
...inted.
Here are a few extra valid JSON examples, one per block:
{}
[0]
{"__comment": "json doesn't accept comments and you should not be commenting even in this way", "avoid!": "also, never add more than one key per line, like this"}
[{ "why":null} ]
{
"not true": [0, false],
"true": true,...
Getting the location from an IP address [duplicate]
... "CA",
"country": "US",
"phone": 650
}
Here's a PHP example:
$ip = $_SERVER['REMOTE_ADDR'];
$details = json_decode(file_get_contents("http://ipinfo.io/{$ip}/json"));
echo $details->city; // -> "Mountain View"
You can also use it client-side. Here's a simple jQuery example:
$.get(...
Which is the preferred way to concatenate a string in Python?
...
If you have multiple strings (n > 10) "".join(list_of_strings) is still faster
– Mikko Ohtamaa
Aug 29 '12 at 5:34
11
...
How to disassemble one single function using objdump?
...e.g., gdb -batch -ex 'disassemble main' /bin/ls
– hoc_age
Oct 17 '14 at 15:01
3
...
Git merge without auto commit
...merged in (as opposed to a traditional merge) you need to run rm .git/MERGE_HEAD afterward, which will force git to forget that the merge happened.
– Jonn
Feb 27 '16 at 0:23
...