tuples

问题 I have a list of tuples [(1,'a','%',"yes"),(2,'b','[',"no"),(3,'c',']',"ok")] . How can I show this list as output in the form of [(1,a,%,yes),(2,b,[,no),(3,c,],ok)] ? 回答1: Looks like the transformation you wish to make is to strip out quote characters? If so, filtering the results of calling show on your data will be enough: > let x = [(1,'a','%',"yes"),(2,'b','[',"no"),(3,'c',']',"ok")] Then apply a filter, > putStrLn . filter (`notElem` "'\"") . show $ x [(1,a,%,yes),(2,b,[,no),(3,c,],ok)]

问题 I just noticed that if you want to create a tuple with single element, being a tuple itself, you cannot do it with constructor tuple only with (,) syntax. Why is that? Example: >>> tuple(list('abc')) ('a', 'b', 'c') >>> tuple(tuple(list('abc'))) ('a', 'b', 'c') >>> (tuple(list('abc')),) (('a', 'b', 'c'),) But then it holds for a list >>> tuple([1],) (1,) >>> tuple([1]) (1,) 回答1: I don't really see the issue, this adheres to the documentation: class tuple(object) | tuple() -> empty tuple |

问题 I need a function which would be taking variadic arguments . The number of arguments may vary from 1 to N. def abc(*args): print "ABC" print args print len(args) def abc1(*args): print "ABC1" print args print len(args) print "------------" tup = ("Hello123") abc(*tup) abc1(tup) tup = ("Hello123", "Hello1234") abc(*tup) abc1(tup) The ouput of the above program is; ABC ('H', 'e', 'l', 'l', 'o', '1', '2', '3') 8 ABC1 ('Hello123',) 1 ------------ ABC ('Hello123', 'Hello1234') 2 ABC1 (('Hello123',

问题 I've written a for_each for tuple s: template <typename Tuple, typename F, size_t begin, size_t end> enable_if_t<begin == end || tuple_size<Tuple>::value < end> for_each(Tuple&, F&&) { } template <typename Tuple, typename F, size_t begin = 0U, size_t end = tuple_size<Tuple>::value> enable_if_t<begin < end && tuple_size<Tuple>::value >= end> for_each(Tuple& t, F&& f) { f(get<begin>(t)); for_each<Tuple, F, begin + 1, end>(t, forward<F>(f)); } [Live Example] But Yakk's answer to this question

问题 I am processing some data with the following format: String s = "{(30,2884090,1410450570357,235),(30,2863348,1410451100148,285)}" Some doubts beset me: Are there two entries (tuples) in this String? Is there any off-the-shelf data structure I can use to parse this? Is there any way to figure out a pattern matching which can return a list of two Strings for the given String ? 回答1: As far as I know, Java API does not have something that can be used out-of-box. You need to write a small parser

问题 This question already has answers here : What are the differences between type() and isinstance()? (7 answers) Closed 2 years ago . I found this 3 ways to check it, but I don't know which of them is the best: x = ['Bla', 'Bla', 'Bla', 'etc'] if isinstance(a, list): print('Perfect!') if type(a) is list: print('Incredible!') if type(a) == type([]): print('Awesome!') Which of these is better? Also, Can I use these ways to check whether an x is a string, tuple, dictionary, int, float, etc? If

问题 Consider the following Swift code. var a = [(1, 1)] if contains(a, (1, 2)) { println("Yes") } All I need is to check if a contains the tuple but the code leads to error. Cannot find an overload for 'contains' that accepts an argument list of type '([(Int, Int)], (Int, Int))' Why so and how to use contains properly? 回答1: Add the following to your code: func contains(a:[(Int, Int)], v:(Int,Int)) -> Bool { let (c1, c2) = v for (v1, v2) in a { if v1 == c1 && v2 == c2 { return true } } return

问题 This question already has answers here : scala tuple unpacking (5 answers) Closed 4 years ago . I wonder what is the best way to do this. val foo = Some("a") val bar = Some(2) def baz(a: String, b: Int) = if((b % 2) == 0) Some(a+","+b) else None (x zip y) flatMap baz //does not compile of course (x zip y) flatMap { x => baz(x._1, x._2) } //ugly I would presume that Odersky et al. have another trick up theirs sleeve to reduce the noise in this example. So the question is how to fight the

问题 This question already has answers here : scala tuple unpacking (5 answers) Closed 4 years ago . I wonder what is the best way to do this. val foo = Some("a") val bar = Some(2) def baz(a: String, b: Int) = if((b % 2) == 0) Some(a+","+b) else None (x zip y) flatMap baz //does not compile of course (x zip y) flatMap { x => baz(x._1, x._2) } //ugly I would presume that Odersky et al. have another trick up theirs sleeve to reduce the noise in this example. So the question is how to fight the

问题 Python has (1,) for a single element tuple. In Scala, (1,2) works for Tuple2(1,2) but we must use Tuple1(1) to get a single element tuple. This may seem like a small issue but designing APIs that expect a Product is a pain to deal for users that are passing single elements since they have to write Tuple1(1). Maybe this is a small issue, but a major selling point of Scala is more typing with less typing. But in this case it seems it's more typing with more typing. Please tell me: 1) I've