elements

I need to choose some elements from the given list, knowing their index. Let say I would like to create a new list, which contains element with index 1, 2, 5, from given list [-2, 1, 5, 3, 8, 5, 6]. What I did is: a = [-2,1,5,3,8,5,6] b = [1,2,5] c = [ a[i] for i in b] Is there any better way to do it? something like c = a[b] ? You can use operator.itemgetter : from operator import itemgetter a = [-2, 1, 5, 3, 8, 5, 6] b = [1, 2, 5] print(itemgetter(*b)(a)) # Result: (1, 5, 5) Or you can use numpy : import numpy as np a = np.array([-2, 1, 5, 3, 8, 5, 6]) b = [1, 2, 5] print(list(a[b])) #

I was wondering, JavaScript offers a variety of methods to get the first child element from any element, but which is the best? By best, I mean: most cross-browser compatible, fastest, most comprehensive and predictable when it comes to behaviour. A list of methods/properties I use as aliases: var elem = document.getElementById('container'); var child = elem.children[0]; var child = elem.firstElementChild; // == children[0] This works for both cases: var child = elem.childNodes[0]; // or childNodes[1], see below That’s in case of forms, or <div> iteration. If I might encounter text elements: