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How to use Active Support core extensions
I have Active Support 3.0.3 installed and Rails 3.0.3 with Ruby 1.8.7.
5 Answers
5
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How does Duff's device work?
I've read the article on Wikipedia on the Duff's device , and I don't get it. I am really interested, but I've read the explanation there a couple of times and I still don't get it how the Duff's device works.
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How to center canvas in html5
...center according to the size of the browser window. The canvas is 800x600.
And if the window gets below 800x600, it should resize as well(but that's not very important at the moment)
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MySQL Update Inner Join tables query
...px = g.latitude,
b.mapy = g.longitude
WHERE (b.mapx = '' or b.mapx = 0) and
g.latitude > 0
Update:
Since you said the query yielded a syntax error, I created some tables that I could test it against and confirmed that there is no syntax error in my query:
mysql> create table business ...
Is there a library function for Root mean square error (RMSE) in python?
...lso known as MSE, RMD, or RMS. What problem does it solve?
If you understand RMSE: (Root mean squared error), MSE: (Mean Squared Error) RMD (Root mean squared deviation) and RMS: (Root Mean Squared), then asking for a library to calculate this for you is unnecessary over-engineering. All these me...
Cross Browser Flash Detection in Javascript
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With jQuery and swfobject, this is the code I used to add Modernizr-style html class names: $('html').addClass(typeof swfobject !== 'undefined' && swfobject.getFlashPlayerVersion().major !== 0 ? 'flash' : 'no-flash');
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Immutable vs Mutable types
... changing what the variable refers to. A mutable type can change that way, and it can also change "in place".
Here is the difference.
x = something # immutable type
print x
func(x)
print x # prints the same thing
x = something # mutable type
print x
func(x)
print x # might print something differe...
Differences in boolean operators: & vs && and | vs ||
I know the rules for && and || but what are & and | ? Please explain these to me with an example.
11 Ans...
Detail change after Git pull
... branches, with an asterisk by the currently checked-out one, with the command git branch. The current branch name is also printed along with the output of git status. I highly recommend skimming the man pages of commands to use - it's a great way to slowly pick up some knowledge.
And your last que...
Why does Math.round(0.49999999999999994) return 1?
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Summary
In Java 6 (and presumably earlier), round(x) is implemented as floor(x+0.5).1 This is a specification bug, for precisely this one pathological case.2 Java 7 no longer mandates this broken implementation.3
The problem
0.5+0.49999999...