数组是什么?
返回值:添加元素后的数组长度
var names = ["孙悟空","猪八戒","沙悟净"];
var len = names.**push("lhm")**;
console.log(names,len);
运行结果:
返回值:被删除的元素
var names = ["孙悟空","猪八戒","沙悟净"];
var ele = names.pop();
console.log(names,ele);
运行结果:
返回值:被删除的元素
var names = ["孙悟空","猪八戒","沙悟净"];
var ele2 = names.shift();
console.log(names,ele2);
运行结果:
返回值:被删除的元素
var names = ["孙悟空","猪八戒","沙悟净"];
var len2 = names.unshift("unshift1","unshift2");
console.log(names,len2);
运行结果:
返回值:排序后的数组
var arr = ["a","bc","abc","db"];
var nums = [2,34,12,43,4,8];
console.log(arr.sort());
console.log(nums.sort());
nums.sort(function(a,b){ //对数组中的数字进行升序排列
return a-b;
});
console.log(nums);
运行结果:
返回值:反转后的数组
var nums = [2,34,12,43,4,8];
nums.reverse();
console.log(nums);
运行结果:
返回值:返回值:拼接后的字符串
var arr = ["a","bc","abc","db"];
var str = arr.join("+");
console.log(arr);
console.log(str);
运行结果:
返回值:返回值:合并后的新数组
var arr = ["a","bc","abc","db"];
var arr2 = [1,21,34,66];
var arr3 = ["张","李","王"];
var newArr = arr2.concat(arr,arr3);
console.log(newArr);
运行结果:
返回值:新数组
var names = ["孙悟空","猪八戒","沙悟净","白龙马","唐僧"];
var newArry = names.slice(2,4);
console.log(newArry);
运行结果:
返回值:被删除的元素组成的数组
var names = ["孙悟空","猪八戒","沙悟净","白龙马","唐僧"];
var dele = names.splice(1,2);
console.log(names);
console.log(dele);
names.splice(0,2,"李","会");
console.log(names);
运行结果:
返回值:给定元素的第一个索引,找不到则返回-1
var numbers = [3,2,9,6,9];
var i = numbers.indexOf(0);
console.log(i);
console.log(numbers.indexOf(9));
var j = numbers.indexOf(9,3);
console.log(j);
运行结果:
返回值:Boolean类型 是:true 否:false
var numbers = [3,2,9,6,8];
console.log(numbers.includes(5));
console.log(numbers.includes(9));
console.log(numbers.includes(9,3));
运行结果:
返回值:undefined
var names = ["孙悟空","猪八戒","沙悟净"];
names.forEach(function(ele,index,array){
console.log(ele,index,array);
})
运行结果:
返回值:存放执行结果的新数组
var numbers = [3,2,6,9];
var newNum = numbers.map(function(e){
return e*2;
});
console.log(newNum);
运行结果:
返回值:满足过滤条件的元素组成的新数组
var arr = ["孙悟空","猪八戒",1,5,"沙悟净","白龙马",65,"唐僧"];
var newArry = arr.filter(function(e,i,arr){
return typeof(e) === "number";
});
console.log(newArry);
运行结果:
返回值:Boolean类型,有返回 true, 没有返回 false
var arr = ["孙悟空","猪八戒",1,5,"沙悟净","白龙马",65,"唐僧"];
var flag = arr.some(function(e,i,arr){
return typeof(e) === "boolean";
});
console.log(flag);
运行结果:
返回值:Boolean类型,都满足返回 true, 否则返回 false
var names = ["孙悟空","猪八戒","沙悟净"];
var flag1 = names.every(function(e,i,arr){
return typeof(e) === "string";
});
console.log(flag1);
运行结果:
利用周末时间把这些常用的数组方法整理出来跟大家分享
希望对你有所帮助
如果发现有错误的地方,还请多多指教!
本文地址:https://blog.csdn.net/weixin_42678796/article/details/107127262
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