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Run a callback only if an attribute has changed in Rails
...ods/Dirty.html
Before Saving (OPTIONAL CHANGE)
After modifying an object and before saving to the database, or within the before_save filter:
changes should now be changes_to_save
changed? should now be has_changes_to_save?
changed should now be changed_attribute_names_to_save
<attribute>_...
How can I check if a background image is loaded?
...t it in CSS — so images are start downloading before css file — it's called preloading.
– jcubic
Feb 20 '11 at 17:05
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What is the fastest way to check if a class has a function defined?
I'm writing an AI state space search algorithm, and I have a generic class which can be used to quickly implement a search algorithm. A subclass would define the necessary operations, and the algorithm does the rest.
...
How to convert Java String into byte[]?
...m you appear to be wrestling with is that this doesn't display very well. Calling toString() will just give you the default Object.toString() which is the class name + memory address. In your result [B@38ee9f13, the [B means byte[] and 38ee9f13 is the memory address, separated by an @.
For display ...
Django: How to manage development and production settings?
...s you define environment variables in an "environment" (.env) file.
Finally, note that you can take advantage of the PYTHONPATH variable to store the settings in a completely different location (e.g. on a production server, storing them in /etc/). This allows for separating configuration from ap...
What is the use of having destructor as private?
...en "friend"ed) responsible for counting the number of references to itself and delete it when the number hits zero. A private dtor would prevent anybody else from deleting it when there were still references to it.
For another instance, what if you have an object that has a manager (or itself) tha...
How to stop flask application without using ctrl-c
I want to implement a command which can stop flask application by using flask-script.
I have searched the solution for a while. Because the framework doesn't provide "app.stop()" API, I am curious about how to code this. I am working on Ubuntu 12.10 and Python 2.7.3.
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Interfacing with structs and anonymous unions with c2hs
... postfix: "",
imageUploader: {
brandingHtml: "Powered by \u003ca href=\"https://imgur.com/\"\u003e\u003csvg class=\"svg-icon\" width=\"50\" height=\"18\" viewBox=\"0 0 50 18\" fill=\"none\" xmlns=\"http://www.w3.org/2000/svg\"\u003e\u003cpath d=\"M46.1709 9....
Making a property deserialize but not serialize with json.net
...
There are actually several fairly simple approaches you can use to achieve the result you want.
Let's assume, for example, that you have your classes currently defined like this:
class Config
{
public Fizz ObsoleteSetting { get; set;...
Is “inline” without “static” or “extern” ever useful in C99?
...
Actually this excellent answer also answers your question, I think:
What does extern inline do?
The idea is that "inline" can be used in a header file, and then "extern inline" in a .c file. "extern inline" is just how you ins...