tuples

问题 I have this case: std::vector<4_integers> v; What would fit best here? std::tuple solution: std::vector<std::tuple<int,int,int,int>> v; std::array solution: std::vector<std::array<int,4>> v; and why? EDIT (The use case): Sorry for not mentioning that before. I am going to use it as follow: for(const auto& item:v){ some_function(item[0],item[1],item[2],item[3]); // or tuple equivalent } Of course I need to keep them stored because computing the 4 integers is not a thing that I want to repeat

问题 Today I'm trying to create a tuple a little specific (for me at least) and at compile time. I have some basic struct, let say : struct Foo1 { int data; }; struct Foo2 { int data; }; struct Foo3 { int data; }; And another struct but with some template stuff : template < typename T, size_t Size > struct Metadata { using type = T; std::bitset<Size> bitset; }; So now I want to create this kind of tuple : constexpr std::tuple<Metadata<Foo1, 3>, Metadata<Foo2, 3>, Metadata<Foo3, 3>> test { {0}, {0}

问题 I have some financial data gathered at a List[(Int, Double)], like this: val snp = List((2001, -13.0), (2002, -23.4)) With this, I wrote a formula that would transform the list, through map, into another list (to demonstrate investment grade life insurance), where losses below 0 are converted to 0, and gains above 15 are converted to 15, like this: case class EiulLimits(lower:Double, upper:Double) def eiul(xs: Seq[(Int, Double)], limits:EiulLimits): Seq[(Int, Double)] = { xs.map(item => (item

问题 I have some financial data gathered at a List[(Int, Double)], like this: val snp = List((2001, -13.0), (2002, -23.4)) With this, I wrote a formula that would transform the list, through map, into another list (to demonstrate investment grade life insurance), where losses below 0 are converted to 0, and gains above 15 are converted to 15, like this: case class EiulLimits(lower:Double, upper:Double) def eiul(xs: Seq[(Int, Double)], limits:EiulLimits): Seq[(Int, Double)] = { xs.map(item => (item

问题 While trying to port some code to compile in linux I get peculiar compilation errors. Searching through the codebase I finally manage to get it down to the following code. 5: // include and using statements 6: template<typename RT, typename T1> 7: RT func(tuple<T1> const& t) { 8: return t.get<0>(); 9: } 10: // test code Trying to use it I get the error: test.cpp: In function <functionName>: test.cpp:8: error: expected primary-expression before ‘)’ token The code works fine in Visual Studio

问题 This question already has an answer here : Nested arguments not compiling (1 answer) Closed 5 years ago . For some reason in python everytime I try to define tuples in a function I get a syntax error. For example I have a function that adds vectors to the program, it looks like this: def add_vectors((angle_1, l_1),(angle_2, l_2)): x=math.sin(angle1)*l_1+math.sin(angle2)*l_2 y=math.cos(angle1)*l_1+math.cos(angle2)*l_2 angle=0.5*math.pi-math.atan2(y, x) length=math.hypot(x, y) return (angle,

问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 2 years ago . I have confused with lists, tuples, sets and dictionaries someone give me clear cut idea . Give me the difference from your understanding don't give the text book definitions. 回答1: A list is a sequence of elements in a specific order. You can access elements with a numerical index

问题 I need to separate a tuple based on a value from a nested dictionary as below and put it in another list. I want to separate tuple with values 'bb' original_list= [[('aa','1'),('bb','2')],[('cc','3'),('bb','4')],[('dd','5'),('dd','6')]] I need two lists as below, final_list= [[('aa','1')],[('cc','3')],[('dd','5'),('dd','6')]] deleted_list = [[('bb','2')],[('bb','4')]] I used the following recursive code, def remove_items(lst, item): r = [] for i in lst: if isinstance(i, list): r.append(remove

问题 I need to separate a tuple based on a value from a nested dictionary as below and put it in another list. I want to separate tuple with values 'bb' original_list= [[('aa','1'),('bb','2')],[('cc','3'),('bb','4')],[('dd','5'),('dd','6')]] I need two lists as below, final_list= [[('aa','1')],[('cc','3')],[('dd','5'),('dd','6')]] deleted_list = [[('bb','2')],[('bb','4')]] I used the following recursive code, def remove_items(lst, item): r = [] for i in lst: if isinstance(i, list): r.append(remove

问题 I'm new to Python and have looked at quite a bit of documentation to figure out what is going on, but haven't had any luck. I have a list of tuples that I need to convert to lowercase and perform mathematical operations on all values in the list. The "E", needs to become an "e" in order to perform mathematical operations. If there is a single value in a given list of tuples, the following works: EarthU = ['1.3719107E+11', '8.3311764E-02', '2.2719107E+11', '1.4880643E+03'] earthU = [element