push()实现
Array.prototype.push = function() {
for (var i = 0; i < arguments.length; i++) {
this[this.length] = arguments[i];
}
}
unshift()实现
Array.prototype.unshift = function() {
var output = [];
for (var i = 0; i < arguments.length; i++) {
output[output.length] = arguments[i];
};
for (var i = 0; i < this.length; i++) {
output[output.length] = this[i];
};
for (var i = 0; i < output.length; i++) {
this[i] = output[i];
};
return this.length;
}
reverse()实现
Array.prototype.reverse = function() {
var output = [];
for (var i = this.length - 1; i >= 0; i--) {
output.push(this[i]);
}
for (var i = 0; i < output.length; i++) {
this[i] = output[i];
};
return this.length;
}
sort()自定义排序方法
- 规则：
- 自定义的排序方法，必须传入两个形参
- 返回的值为负数时，前面的数字在前，反之，后面的在前
- 返回0时不变化
return a-b 为升序排序，b-a为降序排序
