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How can I use if/else in a dictionary comprehension?
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@Marcin's answer covers it all, but just in case someone wants to see an actual example, I add two below:
Let's say you have the following dictionary of sets
d = {'key1': {'a', 'b', 'c'}, 'key2': {'foo', 'bar'}, 'key3': {'so', 'sad'}}
and you want ...
Defining a function with multiple implicit arguments in Scala
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They must all go in one parameter list, and this list must be the last one.
def myfun(arg:String)(implicit p1: String, p2:Int)={}
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Sort a list by multiple attributes?
... how, you can wrap your criteria (functions) in parenthesis:
s = sorted(my_list, key=lambda i: ( criteria_1(i), criteria_2(i) ), reverse=True)
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What does the “===” operator do in Ruby? [duplicate]
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Just like with every other method in Ruby (or actually pretty much any object-oriented language),
a === b
means whatever the author of a's class wants it to mean.
However, if you don't want to confuse the heck out of your colleagues, the convention is that === is the cas...
Best XML Parser for PHP [duplicate]
...saves on memory. You pay for that with not being able to use XPath.
Personally, I find SimpleXml quite limiting (hence simple) in what it offers over DOM. You can switch between DOM and SimpleXml easily though, but I usually dont bother and go the DOM route directly. DOM is an implementation of the...
What is the best algorithm for overriding GetHashCode?
...hroughout the .NET base class libraries. Implementing it properly is especially important to find items quickly in a collection or when determining equality.
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How to get one value at a time from a generator function in Python?
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In Python <= 2.5, use gen.next(). This will work for all Python 2.x versions, but not Python 3.x
In Python >= 2.6, use next(gen). This is a built in function, and is clearer. It will also work in Python 3.
Both of these end up calling a specially named function, next(), wh...
Remove empty array elements
... of strings, you can simply use array_filter(), which conveniently handles all this for you:
print_r(array_filter($linksArray));
Keep in mind that if no callback is supplied, all entries of array equal to FALSE (see converting to boolean) will be removed. So if you need to preserve elements that ...
What's the difference between ES6 Map and WeakMap?
...e: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap):
Keys of WeakMaps are of the type Object only. Primitive data types as
keys are not allowed (e.g. a Symbol can't be a WeakMap key).
Nor can a string, number, or boolean be used as a WeakMap key. A M...
How to sort in mongoose?
...t:{
date_added: -1 //Sort by Date Added DESC
}
},
function(err,allNews){
socket.emit('news-load', allNews); // Do something with the array of 10 objects
})
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