Insert element in Python list after every nth element

I’ve got two one liners. Given: >>> letters = [‘a’,’b’,’c’,’d’,’e’,’f’,’g’,’h’,’i’,’j’] Use enumerate to get index, add ‘x’ every 3rd letter, eg: mod(n, 3) == 2, then concatenate into string and list() it. >>> list(”.join(l + ‘x’ * (n % 3 == 2) for n, l in enumerate(letters))) [‘a’, ‘b’, ‘c’, ‘x’, ‘d’, ‘e’, ‘f’, ‘x’, …

Read more

How to remove all element from array except the first one in javascript

You can set the length property of the array. var input = [‘a’,’b’,’c’,’d’,’e’,’f’]; input.length = 1; console.log(input); OR, Use splice(startIndex) method var input = [‘a’,’b’,’c’,’d’,’e’,’f’]; input.splice(1); console.log(input); OR use Array.slice method var input = [‘a’,’b’,’c’,’d’,’e’,’f’]; var output = input.slice(0, 1) // 0-startIndex, 1 – endIndex console.log(output);