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Rails: How do I create a default value for attributes in Rails activerecord's model? [duplicate]
...consider using the before_validation callback.
– tokland
Jul 15 '10 at 10:13
44
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Why is the minimalist, example Haskell quicksort not a “true” quicksort?
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The true quicksort has two beautiful aspects:
Divide and conquer: break the problem into two smaller problems.
Partition the elements in-place.
The short Haskell example demonstrates (1), but not (2). How (2) is done may not be obvious if you don't already know the technique!...
Does it make sense to use “as” instead of a cast even if there is no null check? [closed]
In development blogs, online code examples and (recently) even a book, I keep stumbling about code like this:
13 Answers
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When is layoutSubviews called?
...ith the answer (or any I could find on the net), so I tried it in practice and here is what I got:
init does not cause layoutSubviews to
be called (duh)
addSubview: causes
layoutSubviews to be called on the
view being added, the view it’s being
added to (target view), and all the
subviews of th...
HTML Form: Select-Option vs Datalist-Option
I was wondering what the differences are between Select-Option and Datalist-Option. Is there any situation in which it would be better to use one or the other? An example of each follows:
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Bash script to calculate time elapsed
...a script in bash to calculate the time elapsed for the execution of my commands, consider:
10 Answers
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Data structure: insert, remove, contains, get random element, all at O(1)
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Consider a data structure composed of a hashtable H and an array A. The hashtable keys are the elements in the data structure, and the values are their positions in the array.
insert(value): append the value to array and let i be its index in A. Set H[value]=i.
remove(value)...
How to pass a function as a parameter in Java? [duplicate]
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Java 8 and above
Using Java 8+ lambda expressions, if you have a class or interface with only a single abstract method (sometimes called a SAM type), for example:
public interface MyInterface {
String doSomething(int param1, S...
.NET 4.0 has a new GAC, why?
... it mean now we have to manage two GACs, one for .NET 2.0-3.5 applications and the other for .NET 4.0 applications?
3 Answe...
newline in [duplicate]
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This should now work with Internet Explorer, Firefox v12+ and Chrome 28+
<img src="'../images/foo.gif'"
alt="line 1&#013;line 2" title="line 1&#013;line 2">
Try a JavaScript tooltip library for a better result, something like OverLib.
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