如何计算 Java 脚本数组中的项目，但仅当项目彼此相邻时？

Question

I have an array for example like this
{John, John, John, Maria, Peter, Peter, Maria, Anna, Anna, Maria, Maria, Peter}
I need to get result like

1 -> 3
2 -> 1
3 -> 2
4 -> 1
5 -> 2
6 -> 2
7 -> 1

Answer 1

I group the names, then I count them.

 const array = ['John', 'John', 'John', 'Maria', 'Peter', 'Peter', 'Maria', 'Anna', 'Anna', 'Maria', 'Maria', 'Peter']; let final = []; const count = array.forEach(item => { //check whether the last item in the array has the same name if ( final[final.length - 1] && final[final.length-1][0] === item ) { final[final.length -1].push(item) } else { //if different name then create a new grouping final[final.length] = [item] } }) console.log(final.map(item => item.length)) //returns the size of each group console.log('final array', final)