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Elegant way to invert a map in Scala
... different keys associated with same values. So, if you are interested in knowing all the keys, here's the code:
scala> val m = Map(1 -> "a", 2 -> "b", 4 -> "b")
scala> m.groupBy(_._2).mapValues(_.keys)
res0: Map[String,Iterable[Int]] = Map(b -> Set(2, 4), a -> Set(1))
...
Compare object instances for equality by their attributes
...lemented
return self.foo == other.foo and self.bar == other.bar
Now it outputs:
>>> x == y
True
Note that implementing __eq__ will automatically make instances of your class unhashable, which means they can't be stored in sets and dicts. If you're not modelling an immutable ty...
Do I need dependency injection in NodeJS, or how to deal with …?
... dbCon = require('./lib/mydbconnection'); //wherever the file is stored
//now do something with the connection
var connection = dbCon.fetchConnection(); //mydbconnection.js is responsible for pooling, reusing, whatever your app use case is
//come TEST time of SuperCoolWebApp, you can set the requi...
Can scrapy be used to scrape dynamic content from websites that are using AJAX?
... a JSON file:
Which presents all the information I'm looking for.
From now, I must implement all this knowledge in scrapy. Let's define the spider for this purpose:
class spider(BaseSpider):
name = 'RubiGuesst'
start_urls = ['http://www.rubin-kazan.ru/guestbook.html']
def parse(sel...
How to solve Operator '!=' cannot be applied to operands of type 'T' and 'T' [duplicate]
...os: Yeah I wonder how many people are using the wrong method in their code now...
– user541686
Oct 21 '13 at 21:14
...
Remove by _id in MongoDB console
... new for the ObjectId.
Also, note that in some drivers/tools, remove() is now deprecated and deleteOne or deleteMany should be used instead.
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MySQL get the date n days ago as a timestamp
...B will do part of it depending on what you want
mysql> SELECT DATE_SUB(NOW(), INTERVAL 30 day);
2009-06-07 21:55:09
mysql> SELECT TIMESTAMP(DATE_SUB(NOW(), INTERVAL 30 day));
2009-06-07 21:55:09
mysql> SELECT UNIX_TIMESTAMP(DATE_SUB(NOW(), INTERVAL 30 day));
1244433347
...
Java: Date from unix timestamp
...ent the
specified number of milliseconds since
the standard base time known as "the
epoch", namely January 1, 1970,
00:00:00 GMT.
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Semantic Issue: Property's synthesized getter follows Cocoa naming convention for returning 'owned'
... to synthesize it in the .m file (I have done this before with no issues). Now, I came across this: "Semantic Issue: Property's synthesized getter follows Cocoa naming convention for returning 'owned' objects."
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Python decorators in classes
...
Thanks Michael, only now saw that this is what I wanted.
– hcvst
Jan 18 '11 at 16:05
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