javascript - 如何将 "summarize"整数数组转换为具有范围的字符串？

Question

假设您输入了 Array=[1,2,3,5,7,9,10,11,12,15]

输出应该是1-3,5,7,9-12,15

我正在寻找有关我的尝试和其他可能解决方案的反馈。这是我在 javascript 中的尝试:

var min = 0;
var max = -1;

function summarize(array) {
    var sumString = "";
    var prevVal = -1;

    array.forEach(function(currVal, index) {
        if (index > 0) {
            prevVal = array[index - 1];
        }
        if (index === 0) {
            min = currVal;
            max = currVal;
        } else if (currVal - prevVal === 1) {
            max = currVal;
        } else if (min !== max && max !== -1) {
            sumString += min + "-" + max + (index < array.length - 1 ? "," : "");
            min = currVal;
            max = -1;
        } else {
            sumString += min + (index < array.length - 1 ? "," : "");
        }

        if (index === array.length - 1) {
            if (max === -1) {
                sumString += "," + min;
            } else {
                sumString += min + "-" + max;
            }
        }
    });
    return sumString;
}

Answer 1

下面是一个稍微简短的实现:

var i = 0, prev, arr = [1,2,3,5,7,9,10,11,12,15], out = [];
for(i=0; i<arr.length; prev = arr[i], i++) {

    // if the current number is not prev+1, append it to out
    // Note that we are adding it as a string, to ensure that 
    // subsequent calls to `split()` (see else part) works
    if(prev !== arr[i] - 1) out.push(String(arr[i]));

    // if the current number is prev+1, modify the last value
    // in out to reflect it in the RHS of - (hyphen)
    else out[out.length - 1] = [out[out.length - 1].split('-')[0], String(arr[i])].join('-');
}

// out => ["1-3", "5", "7", "9-12", "15"]