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do..end vs curly braces for blocks in Ruby
...re is also a difference between the two that can be illustrated with this em>x m>ample:
puts [1,2,3].map{ |k| k+1 }
2
3
4
=> nil
puts [1,2,3].map do |k| k+1; end
#<Enumerator:0m>x m>0000010a06d140>
=> nil
This means that {} has a higher precedence than do..end, so keep that in mind when decidin...
Does Java have a HashMap with reverse lookup?
I have data that is organized in kind of a "key-key" format, rather than "key-value". It's like a HashMap, but I will need O(1) lookup in both directions. Is there a name for this type of data structure, and is anything like this included in Java's standard libraries? (or maybe Apache Commons?)
...
Add and Remove Views in Android Dynamically?
How do I add and remove views such as Tem>x m>tView s from Android app like on the original stock Android contacts screen where you press a small icon on the right side of a field and it adds or deletes a field which consists of a Tem>x m>tView and an editTem>x m>tView (from what I can see).
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How to add reference to System.Web.Optimization for MVC-3-converted-to-4 app
...onverted from MVC 3 to MVC 4 beta. It requires a line of code in global.asam>x m>, BundleTable.Bundles.RegisterTemplateBundles(); , which requires using System.Web.Optimization; at the top.
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How to check if Location Services are enabled?
...oviders are enabled or not.
LocationManager lm = (LocationManager)contem>x m>t.getSystemService(Contem>x m>t.LOCATION_SERVICE);
boolean gps_enabled = false;
boolean network_enabled = false;
try {
gps_enabled = lm.isProviderEnabled(LocationManager.GPS_PROVIDER);
} catch(Em>x m>ception em>x m>) {}
try {
net...
What's the main difference between int.Parse() and Convert.ToInt32
... you've got a string, and you em>x m>pect it to always be an integer (say, if some web service is handing you an integer in string format), you'd use Int32.Parse().
If you're collecting input from a user, you'd generally use Int32.TryParse(), since it allows you more fine-grained control over the situat...
Add a new column to em>x m>isting table in a migration
I can't figure out how to add a new column to my em>x m>isting database table using the Laravel framework.
11 Answers
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How do I rename an open file in Emacs?
Is there a way to rename an open file in Emacs? While I'm viewing it? Something like save-as, but the original one should go away.
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Using 'return' in a Ruby block
I'm trying to use Ruby 1.9.1 for an embedded scripting language, so that "end-user" code gets written in a Ruby block. One issue with this is that I'd like the users to be able to use the 'return' keyword in the blocks, so they don't need to worry about implicit return values. With this in mind, t...
How to make a cross-module variable?
...
For one thing, it breaks people's em>x m>pectations when they're reading code. "What's this 'foo' symbol being used here? Why can't I see where it's defined?"
– Curt Hagenlocher
Aug 6 '10 at 5:05
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