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How to check null objects in jQuery
I'm using jQuery and I want to check the existence of an element in my page. I have written following code, but it's not working:
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How to set default values in Rails?
...ove the default"
end
end
Because ActiveRecord autodiscovers your table and column properties, this will cause the same default to be set in any model using it in any standard Rails app.
However, if you only want default values set in specific cases -- say, it's an inherited model that shares a ...
Saving grid.arrange() plot to file
...
grid.arrange draws directly on a device. arrangeGrob, on the other hand, doesn't draw anything but returns a grob g, that you can pass to ggsave(file="whatever.pdf", g).
The reason it works differently than with ggplot objects, where by default the last plot is being saved if not specified, ...
How to create full compressed tar file using Python?
...zipped tar archive containing a single top-level folder with the same name and contents as source_dir.
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Why do results vary based on curly brace placement?
... return an object (built by the curly braces) with the property javascript and its value of "fantastic", effectively the same as this:
function test() {
var myObject = new Object();
myObject.javascript = "fantastic";
return myObject;
}
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JPA getSingleResult() or null
... doesn't exist or update it if it does. To enable this, I have to findByIdAndForeignKey , if it returned null insert if not then update. The problem is how do I check if it exists? So I tried getSingleResult . But it throws an exception if the
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What is the Swift equivalent of respondsToSelector?
...ional unwrapper operator. This allows you to call a method on an object if and only if the object exists (not nil) and the method is implemented.
In the case where you still need respondsToSelector:, it is still there as part of the NSObject protocol.
If you are calling respondsToSelector: on an O...
Extract date (yyyy/mm/dd) from a timestamp in PostgreSQL
...0'::timestamp::date;
date
------------
2010-01-01
On the other hand you can use date_trunc function. The difference between them is that the latter returns the same data type like timestamptz keeping your time zone intact (if you need it).
=> select date_trunc('day', now());
da...
Min/Max-value validators in asp.net mvc
...t need to implement the IClientValidation interface on the above attribute and return the correct values from the GetClientValidationRules method
– WickyNilliams
Sep 6 '13 at 13:56
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How to change the name of the active scheme in Xcode?
...h to change
Press the "Return" key
It will select the name of the scheme and allow you to edit it.
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