tuples

In this example, is it possible to allow the deduction of the template parameters type of the tuple ? #include<tuple> #include<string> template<class T1, class T2> void fun(std::tuple<T1, T2> t, std::string other){} int main(){ fun(std::tuple<double, int>(2.,3), std::string("other")); // ok fun(std::make_tuple(2.,3), std::string("other")); // ok, but trying to avoid `make_tuple` fun({2.,3},std::string("other")); // desired syntax but // giving compilation error: candidate template ignored: couldn't infer template argument 'T1' void fun(std::tuple<T1, T2> t) } I added the second argument other

Given the following list of tuples... val list = List((1, 2), (1, 2), (1, 2)) ... how do I sum all the values and obtain a single tuple like this? (3, 6) Using the foldLeft method. Please look at the scaladoc for more information. scala> val list = List((1, 2), (1, 2), (1, 2)) list: List[(Int, Int)] = List((1,2), (1,2), (1,2)) scala> list.foldLeft((0, 0)) { case ((accA, accB), (a, b)) => (accA + a, accB + b) } res0: (Int, Int) = (3,6) Using unzip . Not as efficient as the above solution. Perhaps more readable. scala> list.unzip match { case (l1, l2) => (l1.sum, l2.sum) } res1: (Int, Int) = (3

I have strings which look like this one: "(8, 12.25), (13, 15), (16.75, 18.5)" and I would like to convert each of them into a python data structure. Preferably a list (or tuple) of tuples containing a pair of float values. I could do that with eval("(8, 12.25), (13, 15), (16.75, 18.5)") which gives me a tuple of tuples, but I don't think naively evaluating external information would be a wise decision. So I wondered what an elegant pythonic solution might look like. >>> import ast >>> print ast.literal_eval("(8, 12.25), (13, 15), (16.75, 18.5)") ((8, 12.25), (13, 15), (16.75, 18.5)) def parse

What is difference between tuples and records? Both are product types which let you build types from multiple simpler types. Some languages treat tuples as a kind of record. Definitions A tuple is an ordered group of elements, like (10, 25). A record is typically a group of named elements like { "x": 10, "y": 25 } where the value has two fields labelled x and y and the value of field x is 10 . Etymology The word "tuple" comes from the common "-tuple" suffix on "quintuple", "sextuple", "septuple", "octuple" which mean groups of 5, 6, 7, and 8 respectively. The word "record" comes from data

When comparing a tuple with a list like ... >>> [1,2,3] == (1,2,3) False >>> [1,2,3].__eq__((1,2,3)) NotImplemented >>> (1,2,3).__eq__([1,2,3]) NotImplemented ... Python does not deep-compare them as done with (1,2,3) == (1,2,3) . So what is the reason for this? Is it because the mutable list can be changed at any time (thread-safety issues) or what? (I know where this is implemented in CPython, so please don't answer where , but why it is implemented.) You can always "cast" it >>> tuple([1, 2]) == (1, 2) True Keep in mind that Python, unlike for example Javascript, is strongly typed , and

How do you implement (or create) an array sort of a list of tuples? The following was gleaned from my code. Essentially I created an array of tuples and populated it via for loop; after which I tried to sort it. var myStringArray: (String,Int)[]? = nil ... myStringArray += (kind,number) ... myStringArray.sort{$0 > $1} This is what Xcode gave me before I could build: test.swift:57:9: '(String, Int)[]?' does not have a member named 'sort' drewag You have two problems. First, myStringArray is an Optional , you must "unwrap" it before you can call methods on it. Second, there is no > operator for