LeetCode Js-58. Length of Last Word

Given a string s consisting of words and spaces, return the length of the last word in the string.
A word is a maximal substring consisting of non-space characters only.

給予一個有文字與空格的s字串，回傳最後字串的文字長度。
單字是由非空格組成之字串

Example 1:

Input: s = "Hello World"
Output: 5
Explanation: The last word is "World" with length 5.

Solution:

1. 運用.trim()移除字串中，字首前、字尾後的空白。
2. 使用.split(' ')來將字串以空白做切割為陣列。
3. 注意陣列與數列的關係。

word = [a, b, c]
array   0  1  2

Code:

var lengthOfLastWord = function(s) {
    const arr = s.trim().split(' ')
    return arr[arr.length - 1].length
};

FlowChart:
Example 1

step.1
string    1        2
arr = ['Hello', 'World']
array     0        1
arr.length = 2
return arr[arr.length - 1].length 
//arr[1].length => 'World'.length => 5