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Test if string is a number in Ruby on Rails
...def is_number? string
true if Float(string) rescue false
end
And then call it like this:
my_string = '12.34'
is_number?( my_string )
# => true
Extend String Class.
If you want to be able to call is_number? directly on the string instead of passing it as a param to your helper function, t...
Floating point vs integer calculations on modern hardware
...
From my experience, there are many, many variables to performance...especially between integer & floating point math. It varies strongly from processor to processor (even within the same family such as x86) because different processors have different "pipeline" lengths. Also, some operations ...
Class JavaLaunchHelper is implemented in both. One of the two will be used. Which one is undefined [
... Application Project on Eclipse Kepler on Mac OS X with java version "1.7.0_45"
2 Answers
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Failed to execute 'btoa' on 'Window': The string to be encoded contains characters outside of the La
...
If you have UTF8, use this (actually works with SVG source), like:
btoa(unescape(encodeURIComponent(str)))
example:
var imgsrc = 'data:image/svg+xml;base64,' + btoa(unescape(encodeURIComponent(markup)));
var img = new Image(1, 1); // width, height va...
Is there a ceiling equivalent of // operator in Python?
...t shy of an order of magnitude faster than forcing the float division and calling ceil(), provided you care about the speed. Which you shouldn't, unless you've proven through usage that you need to.
>>> timeit.timeit("((5 - 1) // 4) + 1", number = 100000000)
1.7249219375662506
>>>...
push_back vs emplace_back
...h_back(Type&& _Val).
But the real C++0x form of emplace_back is really useful: void emplace_back(Args&&...);
Instead of taking a value_type it takes a variadic list of arguments, so that means that you can now perfectly forward the arguments and construct directly an object into a ...
Getting the name of a child class in the parent class (static context)
...ot possible. in php4 you could implement a terrible hack (examine the debug_backtrace()) but that method does not work in PHP5. references:
30423
37684
34421
edit: an example of late static binding in PHP 5.3 (mentioned in comments). note there are potential problems in it's current implementat...
What is the (function() { } )() construct in JavaScript?
...tion expression. Then look at the last pair (function(){})();, this is normally added to an expression to call a function; in this case, our prior expression.
This pattern is often used when trying to avoid polluting the global namespace, because all the variables used inside the IIFE (like in any ...
How can jQuery deferred be used?
... // or may not have been retrieved using an
// XHR request.
});
Basically, if the value has already been requested once before it's returned immediately from the cache. Otherwise, an AJAX request fetches the data and adds it to the cache. The $.when/.then doesn't care about any of this; all ...
How to change the background color of the options menu?
...
After spending a considerable amount of time trying all the options, the only way I was able to get an app using AppCompat v7 to change the overflow menu background was using the itemBackground attribute:
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar"&...