tuples

I have some values held in a tuple, and I am looking to add another tuple to it element-wise. So I would like functionality like this: std::tuple<int,int> a = {1,2}; std::tuple<int,int> b = {2,4}; std::tuple<int,int> c = a + b; // possible syntax 1 a += b; // possible syntax 2 a += {2,4}; // possible syntax 3 Where the output tuple would have the value {3,6} Was looking at CPP reference , but I couldn't find this functionality. It's possible that this and this question are relevant, however the answers are obfuscated by other complexities. You could also consider using std::valarray since it

If I have a tuple like this var answer: (number: Int, good: Bool) How do I get one of the elements? This doesn't work: answer["number"] I am modeling this question after Swift: Get an array of element from an array of tuples , but my question was a little more basic. I did find the answer buried in the documentation so I am adding my answer below in Q&A format for faster searching in the future. According to the documentation (scroll down to Tuples), there are three ways to do it. Given var answer: (number: Int, good: Bool) = (100, true) Method 1 Put the element variable name within a tuple.

The pairs function needs to do something like this: pairs [1, 2, 3, 4] -> [(1, 2), (2, 3), (3, 4)] pairs [] = [] pairs xs = zip xs (tail xs) You could go as far as import Control.Applicative (<*>) pairs = zip <*> tail but pairs xs = zip xs (tail xs) is probably clearer. Just for completeness, a more "low-level" version using explicit recursion: pairs (x:xs@(y:_)) = (x, y) : pairs xs pairs _ = [] The construct x:xs@(y:_) means "a list with a head x , and a tail xs that has at least one element y ". This is because y doubles as both the second element of the current pair and the first element of

Is there any way in python to use a tuple as the indices for a slice? The following is not valid: >>> a = range(20) >>> b = (5, 12) # my slice indices >>> a[b] # not valid >>> a[slice(b)] # not valid >>> a[b[0]:b[1]] # is an awkward syntax [5, 6, 7, 8, 9, 10, 11] >>> b1, b2 = b >>> a[b1:b2] # looks a bit cleaner [5, 6, 7, 8, 9, 10, 11] It seems like a reasonably pythonic syntax so I am surprised that I can't do it. (update) And the solution turns out to be: >>> a[slice(*b)] [5, 6, 7, 8, 9, 10, 11] You can use Python's *args syntax for this: >>> a = range(20) >>> b = (5, 12) >>> a[slice(*b)] [5

That is, I'd like to have a tuple of values. The use case on my mind: Dictionary<Pair<string, int>, object> or Dictionary<Triple<string, int, int>, object> Are there built-in types like Pair or Triple? Or what's the best way of implementing it? Update There are some general-purpose tuples implementations described in the answers, but for tuples used as keys in dictionaries you should additionaly verify correct calculation of the hash code. Some more info on that in another question . Update 2 I guess it is also worth reminding, that when you use some value as a key in dictionary, it should be

I am not sure if I can make myself clear but will try. I have a tuple in python which I go through as follows (see code below). While going through it, I maintain a counter (let's call it 'n') and 'pop' items that meet a certain condition. Now of course once I pop the first item, the numbering all goes wrong, how can I do what I want to do more elegantly while removing only certain entries of a tuple on the fly? for x in tupleX: n=0 if (condition): tupleX.pop(n) n=n+1 As DSM mentions, tuple 's are immutable, but even for lists, a more elegant solution is to use filter : tupleX = filter(str

In VS2017 RC, when you tried to use new tuple syntax, you received the following error: CS8179 Predefined type 'System.ValueTuple`X' is not defined or imported In order to use tuple syntax, you had to manually import ValueTuple nuget package into the project. Not a big deal, as it was pre-release version and I thought it will be changed in RTM so it will be enabled by default. Unfortunately in the final release version it is still the case and you have to download nuget package for every single project to use tuple syntax. Is there a way to have tuple syntax enabled for every project by