大约有 46,000 项符合查询结果（耗时：0.0812秒） [XML]
JavaScript null check
... in JavaScript. However, it's always safe to test if the typeof(x) is the string "undefined", even if "x" is not a declared variable:
alert(typeof(x) === 'undefined'); // true
Also, variables can have the "undefined value" if they are not initialized:
var y;
alert(typeof(y) === 'undefined'); //...
PostgreSQL Autoincrement
I'm switching from MySQL to PostgreSQL and was wondering how I can do autoincrement values. I saw in the PostgreSQL docs a datatype "serial", but I get syntax errors when using it (in v8.0).
...
mysql update column with value from another table
... is perfect in this situation. I also used CONCAT_WS to merge pruduct name and SKU from another table
– vladkras
Jul 16 '14 at 5:43
2
...
Jquery If radio button is checked
...e 'name' attribute of 'postage'
// 2. assigns the onChange/onchange event handler
$('input:radio[name="postage"]').change(
function(){
// checks that the clicked radio button is the one of value 'Yes'
// the value of the element is the one that's checked (as noted by @shef in co...
Ruby: How to turn a hash into HTTP parameters?
...was originally due to the way an earlier version of rails parsed the query string (I seemed to recall it overwriting the previous 'b' values). Started GET "/?a=a&b%5B%5D=c&b%5B%5D=d&b%5B%5D=e" for 127.0.0.1 at 2011-03-10 11:19:40 -0600 Processing by SitesController#index as HT...
When NOT to use yield (return) [duplicate]
...eason
// (a new state machine needs to be generated)
public IEnumerable<string> GetKeys()
{
foreach(string key in _someDictionary.Keys)
yield return key;
}
// DO this
public IEnumerable<string> GetKeys()
{
return _someDictionary.Keys;
}
Avoid using yield return when yo...
Is there a way to list open transactions on SQL Server 2000 database?
... Jul 24 '17 at 5:47
Jibin Balachandran
3,16311 gold badge1818 silver badges3535 bronze badges
answered Dec 15 '10 at 12:45
...
Why should a Java class implement comparable?
...
Here is a real life sample. Note that String also implements Comparable.
class Author implements Comparable<Author>{
String firstName;
String lastName;
@Override
public int compareTo(Author other){
// compareTo should return < 0...
How do you install ssh-copy-id on a Mac?
...d out my brew library was a bit overdue for a refresh. Running brew update and then installing again solved the problem.
– LapplandsCohan
Sep 29 '16 at 18:30
add a comment
...
async at console app in C#? [duplicate]
...
Here is the simplest way to do this
static void Main(string[] args)
{
Task t = MainAsync(args);
t.Wait();
}
static async Task MainAsync(string[] args)
{
await ...
}
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