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find() with nil when there are no records
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Yes, just do:
Challenge.find_by_id(10)
For Rails 4 and 5:
Challenge.find_by(id: 10)
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Equivalent of LIMIT and OFFSET for SQL Server?
...antage here is the parameterization of the offset and limit in case you decide to change your paging options (or allow the user to do so).
Note: the @Offset parameter should use one-based indexing for this rather than the normal zero-based indexing.
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How do I check how many options there are in a dropdown menu?
...tList > option').length;
This assumes your <select> list has an ID of mySelectList.
http://api.jquery.com/length/
http://api.jquery.com/children/
http://api.jquery.com/child-selector/
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How to write iOS app purely in C
... world we wouldn't have to worry about this, but, remember, this is C.
id autoreleasePool = objc_msgSend(objc_msgSend(objc_getClass("NSAutoreleasePool"), sel_registerName("alloc")), sel_registerName("init"));
// Notice the use of CFSTR here. We cannot use an objective-c string
// liter...
Is it a bad practice to use negative margins in Android?
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In 2010, @RomainGuy (core Android engineer) stated that negative margins had unspecified behavior.
In 2011, @RomainGuy stated that you can use negative margins on LinearLayout and RelativeLayout.
In 2016, @RomainGuy stated that they have never been offic...
PHP - find entry by object property from an array of objects
...this
$item = null;
foreach($array as $struct) {
if ($v == $struct->ID) {
$item = $struct;
break;
}
}
See this question and subsequent answers for more information on the latter - Reference PHP array by multiple indexes
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Jquery insert new row into table at a certain index
...$('#my_table > tbody:last').append(newRow); // this will add new row inside tbody
$("table#myTable tr").last().after(newRow); // this will add new row outside tbody
//i.e. between thead and tbody
//.befor...
Understanding the ngRepeat 'track by' expression
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You can track by $index if your data source has duplicate identifiers
e.g.: $scope.dataSource: [{id:1,name:'one'}, {id:1,name:'one too'}, {id:2,name:'two'}]
You can't iterate this collection while using 'id' as identifier (duplicate id:1).
WON'T WORK:
<element ng-repeat="item...
Reference: mod_rewrite, URL rewriting and “pretty links” explained
...ay also look like this:
GET /foo/bar?baz=42 HTTP/1.1
This is just as valid a request for a URL, and it has more obviously nothing to do with files.
The web server is an application listening on a port, accepting HTTP requests coming in on that port and returning a response. A web server is entir...
Warning: Null value is eliminated by an aggregate or other SET operation in Aqua Data Studio
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You would mostly be using COUNT to summarize over a UID. Therefore
COUNT([uid]) will produce the warning:
Warning: Null value is eliminated by an aggregate or other SET operation.
whilst being used with a left join, where the counted object does not exist.
Using COUNT(...