大约有 40,000 项符合查询结果（耗时：0.0842秒） [XML]
What's the difference between backtracking and depth first search?
...at could be made at this state. I think lcn's answer, that backtracking usually means DFS on the (usually implicit) search tree generated during recursion, comes closest to the truth.
– j_random_hacker
Jul 27 '13 at 2:44
...
How to sum all the values in a dictionary?
... I don't know if you love python, if you love python 3, or if really are referring to a python 2
– Lucas Vazquez
Sep 23 '19 at 20:19
1
...
Pushing an existing Git repository to SVN
I've been doing all my work in Git and pushing to GitHub. I've been very happy with both the software and the site, and I have no wish to change my working practices at this point.
...
How serious is this new ASP.NET security vulnerability and how can I workaround it?
...add an extra step to protect your sites with a custom URLScan rule.
Basically make sure you provide a custom error page so that an attacker is not exposed to internal .Net errors, which you always should anyways in release/production mode.
Additionally add a random time sleep in the error page to...
Do sessions really violate RESTfulness?
Is using sessions in a RESTful API really violating RESTfulness? I have seen many opinions going either direction, but I'm not convinced that sessions are RESTless . From my point of view:
...
How does PHP 'foreach' actually work?
...r the simplest case is Traversable objects, as for these foreach is essentially only syntax sugar for code along these lines:
foreach ($it as $k => $v) { /* ... */ }
/* translates to: */
if ($it instanceof IteratorAggregate) {
$it = $it->getIterator();
}
for ($it->rewind(); $it->v...
How can I remove a specific item from an array?
... first match of 5 from [2,5,9,1,5,8,5]), while the second function removes all occurrences:
function removeItemOnce(arr, value) {
var index = arr.indexOf(value);
if (index > -1) {
arr.splice(index, 1);
}
return arr;
}
function removeItemAll(arr, value) {
var i = 0;
...
How to configure postgresql for the first time?
I have just installed postgresql and I specified password x during installation.
When I try to do createdb and specify any password I get the message:
...
Deleting all files in a directory with Python
I want to delete all files with the extension .bak in a directory. How can I do that in Python?
7 Answers
...
Laravel Check If Related Model Exists
...hp 7.2+ you can't use count on the relation object, so there's no one-fits-all method for all relations. Use query method instead as @tremby provided below:
$model->relation()->exists()
generic solution working on all the relation types (pre php 7.2):
if (count($model->relation))
{
...