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Find rows with multiple duplicate fields with Active Record, Rails & Postgres
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User.select(:first,:email).group(:first,:email).having("count(*) > 1").all
(note: not tested, you may need to tweak it)
EDITED to remove id column
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Are there constants in JavaScript?
... const:
const MY_CONSTANT = "some-value";
This will work in pretty much all browsers except IE 8, 9 and 10. Some may also need strict mode enabled.
You can use var with conventions like ALL_CAPS to show that certain values should not be modified if you need to support older browsers or are worki...
What's the status of multicore programming in Haskell?
...012 period, the following things have happened:
2012:
From 2012, the parallel Haskell status updates began appearing in the Parallel Haskell Digest.
2011:
Parallel and Concurrent Programming in Haskell, a tutorial. version 1.1 released by Simon Marlow
Haskell and parallelism, mentioned in an ...
Linux - Install redis-cli only
...sr/local/bin/
With Docker I normally use https://registry.hub.docker.com/_/redis/. If I need to add redis-cli to an image I use the following snippet.
RUN cd /tmp &&\
curl http://download.redis.io/redis-stable.tar.gz | tar xz &&\
make -C redis-stable &&\
cp red...
How can I find an element by CSS class with XPath?
.../div[contains(concat(' ', @class, ' '), ' Test ')]
If you wished to be really certain that it will match correctly, you could also use the normalize-space function to clean up stray whitespace characters around the class name (as mentioned by @Terry):
//div[contains(concat(' ', normalize-space(@...
How to remove line breaks (no characters!) from the string?
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You should be able to replace it with a preg that removes all newlines and carriage returns. The code is:
preg_replace( "/\r|\n/", "", $yourString );
Even though the \n characters are not appearing, if you are getting carriage returns there is an invisible character there. The pr...
Bring a window to the front in WPF
... simply using myWindow.Show() and sometimes it wasn't on top. I placed a call to myWindow.Activate() immediately afterwards and it worked.
– Bermo
Aug 26 '09 at 4:54
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C++11 std::threads vs posix threads
...gcc std::thread is perfectly fine - it has a higher abstraction level, a really good interface and plays nicely with other C++11 classes.
The C++11 std::thread class unfortunately doesn't work reliably (yet) on every platform, even if C++11 seems available. For instance in native Android std::threa...
How do I set the request timeout for one controller action in an asp.net mvc application
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You can set this programmatically in the controller:-
HttpContext.Current.Server.ScriptTimeout = 300;
Sets the timeout to 5 minutes instead of the default 110 seconds (what an odd default?)
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Why does Enumerable.All return true for an empty sequence? [duplicate]
The code creates an empty collection of string, then tries to determine if all the elements in the collection are "ABC".
If you run it, b will be true.
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