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When to use IMG vs. CSS background-image?
...TML IMG tag to display an image, as opposed to a CSS background-image , and vice-versa?
31 Answers
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What is `params.require(:person).permit(:name, :age)` doing in Rails 4?
...tionController::Parameters, which provides several methods such as require and permit.
The require method ensures that a specific parameter is present, and if it's not provided, the require method throws an error. It returns an instance of ActionController::Parameters for the key passed into requi...
Why are Oracle table/column/index names limited to 30 characters?
I can understand that many years ago there would be this kind of limitation, but nowadays surely this limit could easily be increased. We have naming conventions for objects, but there is always a case that turns up where we hit this limit - especially in naming foreign keys.
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Explain the encapsulated anonymous function syntax
...
It doesn't work because it is being parsed as a FunctionDeclaration, and the name identifier of function declarations is mandatory.
When you surround it with parentheses it is evaluated as a FunctionExpression, and function expressions can be named or not.
The grammar of a FunctionDeclaratio...
Copy array by value
...e.log({newArray});
Basically, the slice() operation clones the array and returns a reference to a new array.
Also note that:
For references, strings and numbers (and not the actual object), slice() copies object references into the new array. Both the original and new array refer to the same o...
How to install both Python 2.x and Python 3.x in Windows
...ws 7, but now I need to use the Python Imaging Library (PIL), ImageMagick, and wxPython, all of which require Python 2.x.
1...
Calculating distance between two points, using latitude longitude?
...ween two points.
/**
* Calculate distance between two points in latitude and longitude taking
* into account height difference. If you are not interested in height
* difference pass 0.0. Uses Haversine method as its base.
*
* lat1, lon1 Start point lat2, lon2 End point el1 Start altitude in m...
How do I format a date with Dart?
I have an instance of DateTime and I would like to format that to a String. How do I do that? I want to turn the date into a string, something like "2013-04-20".
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Difference between TCP and UDP?
What is the difference between TCP and UDP?
12 Answers
12
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How to handle Objective-C protocols that contain properties?
...tocol, you have to do everything to make sure anObject works.
@property and @synthesize are at heart two mechanisms that generate code for you. @property is just saying there will be a getter (and/or setter) method for that property name. These days @property alone is enough to also have method...