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What is a memory fence?
...ead/writes occur in the order you expect. For example a 'full fence' means all read/writes before the fence are comitted before those after the fence.
Note memory fences are a hardware concept. In higher level languages we are used to dealing with mutexes and semaphores - these may well be implemen...
Adding :default => true to boolean in existing Rails column
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change_column is a method of ActiveRecord::Migration, so you can't call it like that in the console.
If you want to add a default value for this column, create a new migration:
rails g migration add_default_value_to_show_attribute
Then in the migration created:
# That's the more generic way t...
#ifdef replacement in the Swift language
... After i set the custom flag -DLOCAL, on my #if LOCAl #else #endif, it falls into the #else section. I duplicated the original target AppTarget and rename it to AppTargetLocal & set its custom flag.
– Perwyl Liu
Jul 20 '16 at 6:48
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How to apply a function to two columns of Pandas dataframe
Suppose I have a df which has columns of 'ID', 'col_1', 'col_2' . And I define a function :
12 Answers
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How to send a JSON object over Request with Android?
...impop - Is there any chance that you might be able to provide a simple php script to go along with this? I tried implementing your code, but I for the life of me could not get it to send anything other than NULL.
– kubiej21
Apr 2 '12 at 8:22
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Origin is not allowed by Access-Control-Allow-Origin
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Since they are running on different ports, they are different JavaScript origin. It doesn't matter that they are on the same machine/hostname.
You need to enable CORS on the server (localhost:8080). Check out this site: http://enable-cors.org/
All you need to do is add an HTTP header to...
Collection that allows only unique items in .NET?
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If all you need is to ensure uniqueness of elements, then HashSet is what you need.
What do you mean when you say "just a set implementation"? A set is (by definition) a collection of unique elements that doesn't save element ...
Assembly code vs Machine code vs Object code?
...r and compiler may be invoked together. In other cases, a complicated make script or solution file may be used to tell the environment how to build the final application.
There are also interpreted languages that behave differently. Interpreted languages rely on the machine code of a special interpr...
Python dictionary: Get list of values for list of keys
...n list-comp:
Build list and throw exception if key not found: map(mydict.__getitem__, mykeys)
Build list with None if key not found: map(mydict.get, mykeys)
Alternatively, using operator.itemgetter can return a tuple:
from operator import itemgetter
myvalues = itemgetter(*mykeys)(mydict)
# use ...
How do I make calls to a REST api using C#?
...and this thread is one of the top results when doing a Google search for "call restful service c#".
Current guidance from Microsoft is to use the Microsoft ASP.NET Web API Client Libraries to consume a RESTful service. This is available as a NuGet package, Microsoft.AspNet.WebApi.Client. You will n...