tuples

问题 I have been writing some code in the style of: a1 = b1; a2 = b2; a3 = b3; ... an = bn; Suddenly I realize that for me, and for the context that I am writing the current algorithm (...) is more aesthetically pleasing to write some of these assignments in the form of: (a1, a2, a3, ..., an) = (b1, b2, b3, ..., bn); Now, I would like to know about the impact that this way of writing code can have on the performance. I suppose that here the construction-deconstruction of tuples can be optimized

问题 I have a dictionary - d={'revenues': { '201907': {'aaa.csv':'fdwe34x2'}, '201906':{'ddd.csv':'e4c5q'} }, 'complaints': {'2014': {'sfdwa.csv','c2c2jh'} } } I want to convert it into list of tuples - [ ('revenues','201907','aaa.csv','fdwe34x2'), ('revenues','201906','ddd.csv','e4c5q'), ('complaints','2014','sfdwa.csv','c2c2jh') ] I tried using list comprehensions , but did not help - l = [(k,[(p,q) for p,q in v.items()]) for k,v in d.items()] print(l) [('revenues', [('201907', {'aaa.csv':

问题 I have been working on this for some time and I found this Q/A as a good answer into how I can store a tuple. Now I'm trying to use a function template that will generate this class and the auto key word to generate instances of this object. I'm not getting any compiler errors; yet it isn't generating any data and I can not figure out where I'm going wrong, however, my ostream<<() is generating compiler errors complaining about std::get Here is my class and a few ways of how I'm trying to use

问题 I would like to create a function construct-tuples that consumes a list of length m and a Nat n and produces all possible n-tuples of a list of the elements of the consumed list. The following check-expects give an idea of what the function should produce: (check-expect (construct-tuples '(+ -) 3) '((+ + +) (+ + -) (+ - +) (+ - -) (- + +) (- + -) (- - +) (- - -))) (check-expect (construct-tuples empty 3) (list empty)) (check-expect (construct-tuples '(+ -) 0) (list empty)) (check-expect

问题 I am a little confused if it possible an how to use a variadic tuple as an argument in a function and how to initialize it. template <typename T, Arg ...> void foo (int a, std::tuple<T, sizeof(Arg)> TupleTest); ... foo(TupleTest(2, "TEST", 5.5)); How could that be implemented using c++0x? 回答1: You don't need to get the number of template arguments. Just do this: template <typename... T> void foo(int a, std::tuple<T...> TupleTest); // make_tuple so we don't need to enter all the type names foo

问题 I am very new to CPLEX and am trying to understand a friends example so i may produce a model myself, however I am confused as to how one of the decision variables has been created. The notation is unfamiliar to me and also the fact that they are using a set of tuples as well as ranges in it's definition. Any help explaining what is going on and what the line of code does would be greatly appreciated. tuple bus{int busnumber; float capacity; string start_location; string stop_location; int

问题 I am trying to create a set of dates using DateAdd() function but I am getting errors while trying to pass a set of tuples as parameter. The below code returns a member but I am looking for a set of new dates. WITH Member [EFF INJ DT] AS DATEADD("M",12, [INJURY DATE].CurrentMember) SELECT {[EFF INJ DT]} ON COLUMNS, [INJURY DATE].[DATE].Members ON ROWS FROM [WVWC DATA CUBE FROI SROI] I have the following attempt: WITH Set [EFF INJ DT] AS DATEADD("M",12, [INJURY DATE].CurrentMember) SELECT {

问题 I'm trying to write some code for seeding some test data into the Core Data database in an application I'm developing, about Pokémon. My code for seeding is based on this: http://www.andrewcbancroft.com/2015/02/25/using-swift-to-seed-a-core-data-database/ I am having a slight problem with one thing though. I don't seem to be able to put a nil value inside of a tuple. I'm currently trying to seed some Pokémon Moves into the database. A move can have a bunch of different properties, but which

问题 I have a variadic class template that is used to create a top-level class for a variable number of classes. Each class that is to go in the top-level class is derived from a base class, as there is common functionality for them. I don't know the best way to store the derived classes in the parent class, but still be able to access the full functionality of the derived class. If I store the variadic args in a vector, they'll all be stored as a base class and I can't access the derived

问题 I have 2 dictionaries of key, value pairs like: tokenIDs2number = {(6, 7): 1000000000.0, (22,): 700.0, (12,): 3000.0} tokenIDs2number = {(27, 28): u'South Asia'} The keys are tuples of the index locations of number and location slots in the sentence: GDP in 2007 totaled about $ 1 billion , or about $ 3,000 per capita -LRB- exceeding the average of about $ 700 in the rest of South Asia -RRB- . I want to loop through all the tuples for both the numbers and locations, and remove values from the