大约有 46,000 项符合查询结果（耗时：0.0357秒） [XML]
PostgreSQL create table if not exists
..._mytable()
RETURNS void
LANGUAGE plpgsql AS
$func$
BEGIN
IF EXISTS (SELECT FROM pg_catalog.pg_tables
WHERE schemaname = 'myschema'
AND tablename = 'mytable') THEN
RAISE NOTICE 'Table myschema.mytable already exists.';
ELSE
CREATE TABLE myschema...
using href links inside tag
...
<select name="forma" onchange="location = this.value;">
<option value="Home.php">Home</option>
<option value="Contact.php">Contact</option>
<option value="Sitemap.php">Sitemap</option>...
LINQ: Select an object and change some properties without creating a new object
.... But here is the expanded LINQ expression example.
var query = someList.Select(x => { x.SomeProp = "foo"; return x; })
What this does is use an anonymous method vs and expression. This allows you to use several statements in one lambda. So you can combine the two operations of setting the ...
Difference between Select and ConvertAll in C#
...
Select is a LINQ extension method and works on all IEnumerable<T> objects whereas ConvertAll is implemented only by List<T>. The ConvertAll method exists since .NET 2.0 whereas LINQ was introduced with 3.5.
You s...
Do htmlspecialchars and mysql_real_escape_string keep my PHP code safe from injection?
...nerable to certain attack vectors.
Imagine the following SQL:
$result = "SELECT fields FROM table WHERE id = ".mysql_real_escape_string($_POST['id']);
You should be able to see that this is vulnerable to exploit.
Imagine the id parameter contained the common attack vector:
1 OR 1=1
There's no...
Why shouldn't I use mysql_* functions in PHP?
... 5.5 and above)
$link = mysql_connect('localhost', 'user', 'pass');
mysql_select_db('testdb', $link);
mysql_set_charset('UTF-8', $link);
With PDO: All you need to do is create a new PDO object. The constructor accepts parameters for specifying the database source PDO's constructor mostly takes fo...
Blank HTML SELECT without blank item in dropdown list
...
Just use disabled and/or hidden attributes:
<option selected disabled hidden style='display: none' value=''></option>
selected makes this option the default one.
disabled makes this option unclickable.
style='display: none' makes this option not displayed in older ...
How do I create test and train samples from one dataframe with pandas?
...
scikit learn's train_test_split is a good one.
from sklearn.model_selection import train_test_split
train, test = train_test_split(df, test_size=0.2)
share
|
improve this answer
...
How can I use the $index inside a ng-repeat to enable a class and show a DIV?
...
The issue here is that ng-repeat creates its own scope, so when you do selected=$index it creates a new a selected property in that scope rather than altering the existing one. To fix this you have two options:
Change the selected property to a non-primitive (ie object or array, which makes jav...
Selecting empty text input using jQuery
...ow do I identify empty textboxes using jQuery? I would like to do it using selectors if it is at all possible. Also, I must select on id since in the real code where I want to use this I don't want to select all text inputs.
...