tuples

问题 I want to add elements to a tuple. I found 2 ways to do it. This and this answers say add two tuples. It will create a new tuple a = (1,2,3) b = a + (5,) Where as this says, convert the tuple to list, add the element and then convert it back to tuple a = (1,2,3) tmp = list(a) tmp.insert(3, 'foobar') b = tuple(tmp) Which among these two is efficient in terms of memory and performance? Also, suppose I want to insert an element in the middle of a tuple, is that possible using the first method?

问题 I have an object of class A that may be called with different types and returns changed self on each call. For purpose of this question A will do struct A { A call(const int&) { } A call(const string& s) { } //// } a; So I have a tuple of unknown types: std::tuple<Types...> t; and I want to call a with each tuple element, so I want to get something like: b = a; b = b.call(get<0>(t)); b = b.call(get<1>(t)); b = b.call(get<2>(t)); //... or b = a.call(get<0>(t)).call(get<1>(t)).call(get<2>(t)...

问题 I'm trying to write a program in R that when, given a vector, will return all possible tuples of elements from that vector. For example: tuples(c('a','b','c')) = c('a','b','c'); c('a','b'); c('a','c'), c('b','c'); c('a'); c('b'); c('c') I think it should return a list of vectors. For reference, here is a program that does a similar function in Stata. 回答1: You can use combn : x <- 1:3 unlist(lapply(x, function(n) combn(x, n, simplify=FALSE)), recursive=FALSE) 来源： https://stackoverflow.com

问题 Closed . This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed 3 years ago . The array I'm using is int[,,] and I want to make the first value of each (what I assume to be) tuple in one method and then I want to modify the second two values several times. (in another method) For example: int[,,] MyArrayGet() { int [,,] myArray; int [,,] myArray = new int[9,9,9]; for (int i

问题 If I have this tuple type: std::tuple<int, string, std::tuple<...>, int> How can I traverse it? I've been able to write functions that traverse a flat tuple, but not with nested tuples. The problem seems to be for any implementation of a templated function or type that handles all the conceivable types in a nested tuple, there must be this case: template<typename T> void somefunc(T t) { // Do something to t } Which ends up being the best choice for overload resolution for every type, and you

问题 I am getting a list in which I am saving the results in the following way City Percentage Mumbai 98.30 London 23.23 Agra 12.22 ..... List structure is [["Mumbai",98.30],["London",23.23]..] I am saving this records in form of a list.I need the list to be sort top_ten records.Even if I get cities also, it would be fine. I am trying to use the following logic, but it fails for to provide accurate data if (condition): if b not in top_ten: top_ten.append(b) top_ten.remove(tmp) Any other solution

问题 I'm having a little problem using csv.reader. I have two files: FileA corresponds to 9 geographical coordinates (x (column1) and y(column2), with no headers). The file is save from excel into a csv file. 301506 5918202 301012 5919417 309769 5919926 299337 5924043 299602 5924730 305310 5907794 300634 5927108 303968 5922319 303684 5922062 304882 5922009 FileB which is a random sequence of 9 integers between 0 and 8. The file is save as an csv file from excel. The data are in row 1. 6 3 7 8 5 1

问题 I need to find if my tuple contains only None value. I use this code but i not sure it's the good practice: # coding=utf8 def isOnlyNoneValuesTuple(t): """ test if tuple contains only None values """ if not len(tuple(itertools.ifilter(None, t))): return True else: return False print isOnlyNoneValuesTuple((None,None,None,None,None,None,None,None,None,None,None,None,)) print isOnlyNoneValuesTuple((None,None,None,"val",None,None,None,None,)) Do you know other good practice to test it? Thank you

问题 I have a list of tuples: [(2, Operation.SUBSTITUTED), (1, Operation.DELETED), (2, Operation.INSERTED)] I would like to sort this list in 2 ways: First by its 1st value by ascending value, i.e. 1, 2, 3... etc Second by its 2nd value by reverse alphabetical order, i.e. Operation.SUBSTITITUTED, Operation.INSERTED, Operation, DELETED So the above list should be sorted as: [(1, Operation.DELETED), (2, Operation.SUBSTITUTED), (2, Operation.INSERTED)] How do I go about sort this list? 回答1: Since

问题 Let's say I have the following list of lists of tuples: tuples = [ [ ('2017-04-11', '2000000.00'), ('2017-04-12', '1000000.00'), ('2017-04-13', '3000000.00') ], [ ('2017-04-12', '472943.00'), ('2017-04-13', '1000000.00') ] # ... ] How would I go about grouping them based off of the first element (date) and adding the other element. For instance I'd like something like this: tuples = [('2017-04-11', '2000000.00'), ('2017-04-12', '1472943.00'), ('2017-04-13', '4000000.00')], 回答1: The solution