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How to use redis PUBLISH/SUBSCRIBE with nodejs to notify clients when data values change?
... for some improvements which when I have time I will put online. But right now I am really working hard :$.
– Alfred
Jun 14 '12 at 3:08
1
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Convert a row of a data frame to vector
...tly more explicit way to get to the same result.
As @Josh comments below, if you have a not-completely-numeric (alphabetic, factor, mixed ...) data frame, you need as.character(df[1,]) instead.
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Variable interpolation in the shell
...h}_newstap.sh
or
$filepath\_newstap.sh
_ is a valid character in identifiers. Dot is not, so the shell tried to interpolate $filepath_newstap.
You can use set -u to make the shell exit with an error when you reference an undefined variable.
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Is there a pattern for initializing objects created via a DI container
...my objects and I want to have some initialization parameters that are not known until run-time:
5 Answers
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How can I rename a field for all documents in MongoDB?
...ll your records.
Or you can use the former way:
remap = function (x) {
if (x.additional){
db.foo.update({_id:x._id}, {$set:{"name.last":x.name.additional}, $unset:{"name.additional":1}});
}
}
db.foo.find().forEach(remap);
In MongoDB 3.2 you can also use
db.students.updateMany( {}, { $r...
How to read environment variables in Scala
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Now that I use Scala on a daily basis, I must move the accepted answer to @paradigmatic's answer. It uses Scala API and if used as suggested in the comments can return an Option.
– summerbulb
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Escaping regex string
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Return string with all non-alphanumerics backslashed; this is useful if you want to match an arbitrary literal string that may have regular expression metacharacters in it.
A simplistic example, search any occurence of the provided string optionally followed by 's', and return the match obje...
PSQLException: current transaction is aborted, commands ignored until end of transaction block
...tarted using Postgres... it's really annoying that Postgres does this, and now we have to be really rewrite a big bulk of our program that we are porting from Oracle to Postgres. Why isn't there an option like the first to make it behave like Oracle but without the auto-commit?
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Check that an email address is valid on iOS [duplicate]
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return [emailTest evaluateWithObject:self];
}
@end
And then utilize:
if([@"emailString@email.com" isValidEmail]) { /* True */ }
if([@"InvalidEmail@notreallyemailbecausenosuffix" isValidEmail]) { /* False */ }
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Hidden Features of Java
...d it, never heard of it before.
ThreadLocals are typically not so widely known as a way to store per-thread state.
Since JDK 1.5 Java has had extremely well implemented and robust concurrency tools beyond just locks, they live in java.util.concurrent and a specifically interesting example is the j...