Awesome Function: shuffle

在线演示

原始数据：['红桃J', '黑桃A', '方块8', '梅花6', '黑桃K', '红桃A', '梅花9', '梅花2', '红桃K', '黑桃5']

方法一：数组数据两两交换

const shuffle = array => {
    let count = array.length - 1
    while (count) {
        let index = Math.floor(Math.random() * (count + 1))
        ;[array[index], array[count]] = [array[count], array[index]]
        count--
    }
    return array
}

此方法在测试时踩了一个大坑，因为没有句尾分号，解构赋值的方括号与前一语句混在一起导致了报错，好一会检查不到错误之处，后来终于解决。

方法二：首尾取元素随机插入

const shuffle2 = array => {
    let count = len = array.length
    while (count) {
        let index = Math.floor(Math.random() * len)
        array.splice(index, 0, array.pop())
        count--
    }
    return array
}

或
            
const shuffle2 = array => {
    let count = len = array.length
    while (count) {
        let index = Math.floor(Math.random() * len)
        array.splice(index, 0, array.shift())
        count--
    }
    return array
}

方法三：简单随机抽样重组

const shuffle3 = array => {
    let tempArr = Array.of(...array)
    let newArr = []
    let count = tempArr.length
    while (count) {
        let index = Math.floor(Math.random() * (count - 1))
        newArr.push(tempArr.splice(index, 1)[0])
        count--
    }
    return newArr
}