iterable

问题 I was using sum function in pyhton, and i am clear about it's general structure sum(iterable, start) , but i am unable to get the logic behind the following code test = sum(5 for i in range(5) ) print("output: ", test) output: 25 Please can anyone describe what is happening here, basically here 5 is getting multiplied with 5, and same pattern is there for every sample input. 回答1: Your code is shorthand for: test = sum((5 for i in range(5))) The removal of extra parentheses is syntactic sugar:

问题 I was using sum function in pyhton, and i am clear about it's general structure sum(iterable, start) , but i am unable to get the logic behind the following code test = sum(5 for i in range(5) ) print("output: ", test) output: 25 Please can anyone describe what is happening here, basically here 5 is getting multiplied with 5, and same pattern is there for every sample input. 回答1: Your code is shorthand for: test = sum((5 for i in range(5))) The removal of extra parentheses is syntactic sugar:

问题 i've been trying to get the sum of list that changed its values from a string to int using a function player_hand = [] def card_type(player_hand): card_value = 0 if player_hand[0] == 'A': card_value = 11 if player_hand[0] == 'J': card_value = 10 if player_hand[0] == 'Q': card_value = 10 if player_hand[0] == 'K': card_value = 10 if player_hand[0] == '2': card_value = 2 if player_hand[0] == '3': card_value = 3 if player_hand[0] == '4': card_value = 4 if player_hand[0] == '5': card_value = 5 if

问题 I have the following, which works for int s: extension IterableInt on Iterable<int> { int get max => reduce(math.max); int get min => reduce(math.min); int get sum => reduce((a, b) => a + b); } I wanted to make this more general to include decimals and created this: extension IterableNum on Iterable<num> { num get max => reduce(math.max); num get min => reduce(math.min); num get sum => reduce((a, b) => a + b); } These mostly fail, using the following tests: void main(List<String> args) {

问题 For certain purposes, I need to generate an iterable that lists all the partitions of a list, but with a condition on the subsets lenghts. That is, I want to partition my list in subsets of equal lenght (=3 here), except the last one if the lenght of the list isn't a multiple of 3. i.e. ['a','b','c','d','e'] should give all partitions with 2 subsets of lenght 3 and 2. Namely, if I simply use : [p for p in multiset_partitions(['a','b','c','d','e'],2)] Out: [[['a', 'b', 'c', 'd'], ['e']], [['a'

问题 I need to create a helper method which allows to create a sum of any Iterable<? extends Number>, because we have many vectors and require a fast method to determine the sum, so I created the following method: static Integer sum(Iterable<Integer> it) { Integer result = 0; for(T next : it) { result += next; } return result; } This method only works for ints however, but we also have doubles and longs. Because you can't have two methods with the same signature (Our compiler thinks Integer sum

问题 I need to create a helper method which allows to create a sum of any Iterable<? extends Number>, because we have many vectors and require a fast method to determine the sum, so I created the following method: static Integer sum(Iterable<Integer> it) { Integer result = 0; for(T next : it) { result += next; } return result; } This method only works for ints however, but we also have doubles and longs. Because you can't have two methods with the same signature (Our compiler thinks Integer sum

问题 Is an iterable the same as an iterator, or are they different? It seems, from the specifications, an iterable is an object, say, obj , such that obj[Symbol.iterator] refers to a function, so that when invoked, returns an object that has a next method that can return a {value: ___, done: ___} object: function foo() { let i = 0; const wah = { next: function() { if (i <= 2) return { value: (1 + 2 * i++), done: false } else return { value: undefined, done: true } } }; return wah; // wah is

问题 Is an iterable the same as an iterator, or are they different? It seems, from the specifications, an iterable is an object, say, obj , such that obj[Symbol.iterator] refers to a function, so that when invoked, returns an object that has a next method that can return a {value: ___, done: ___} object: function foo() { let i = 0; const wah = { next: function() { if (i <= 2) return { value: (1 + 2 * i++), done: false } else return { value: undefined, done: true } } }; return wah; // wah is

问题 Say I have a list of tuples, like the following: listo = [('a','1'),('b','0'),('c','2'),('d','0')] If I want the lowest tuple, based on the second index of each tuple, I can customize the min function with a lambda function, like this: min(listo, key=lambda x: x[1]) As it stands, this code would return: In [31]: min(listo, key=lambda x: x[1]) Out[31]: ('b', '0') But this only gives me one tuple, and only the first one it encounters at that. What if I wanted ALL the min tuples? So it returns