new Array()
new Array(len)
new Array([item0,[item1,[item2,...]]]
Method of using array object:
var objArray=new Array ();
objArray.concact([item1[,item2[,....]]]-------------------Concatenate the parameter list to objArray Later, a new array is formed and returned, and the original array is not affected. For example: var arr=["a","b","c"];
arr.concact("d","e") ;
will return an array containing elements from "a" to "e", while arr itself is not affected.
objArray.join(separator)------------- ---Use the character specified by separator as the separator to convert the array into a string. When separator is a comma, its function is the same as toString().
objArray.pop()---------. In layman's terms, it pops the last element of the array. Combined with the push method below, it is possible to use the array as a stack. The pop method returns the value of the last element of the array and decrements the length attribute by 1, which is lost immediately after return. The last element.
objArray.push([value1[,value2[,....]]])-------------Add parameters to the end of the array. For example: [ 1,2,3, 4].push("a","b") will get [1,2,3,4,"a","b"]
objArray.reverse() will get the The elements are reversed. For example: [1,2,3].reverse() will get [3,2,1]. This operation is performed on the original array and also returns the array itself
objArray.shift ()----------Remove the first element of the array and return the value of this element. The nature of this method is very similar to the pop method, which removes the last element. >objArray.slice(start,end)---------- Returns a subset of the array object. The index starts from start (including start) and ends at end (excluding end). The original array does not Affected. For example: [1,2,3,4,5,6].slice(1,4) will get [2,3,4]. When start or end is a negative number, use them plus length. Ground value. For example: [1,2,3,4,5,6].slice(-4,-1) will get [3,4,5]. If end is less than or equal to start, an empty array will be returned.
objArray.sort(comparefn)------- Sort an array according to the size comparison function defined by comparefn. The function comparefn must accept two parameters element1 and element2. If you need element1 to be ranked before element2, you should return a negative number; if you need element1 to be ranked after element2, you should return a positive number. If the two numbers are treated equally (that is, keep the original order), 0 is returned. When comparefn is omitted, the elements are arranged in lexicographic order. For example: for the defined comparison function cmp: function cmp(e1,e2){return e1-e2;} then [3,4,2,7].sort(cmp) will get [2,3,4,7].
objArray.splice(start,deleteCount[,item1,item2[,...]]]) This is a complex function used to complete the deletion, replacement and insertion operations of array elements. Among them, the start parameter indicates the index position to be operated, and deleteCount refers to the number of elements to be deleted from start (including the start position). If deleteCount is omitted, it means that the remaining part of the array is to be deleted from start. [,item1[,item2[,...]]] represents the optional list of elements inserted before start. For example:
var arr=[0,1,2,3,4,5,6];
arr.splice(1,1);
document.write(arr);//Display " 0, 2, 3, 4, 5, 6”
arr=[0,1,2,3,4,5,6];
arr.splice(0,0,"a","b ");
document.write(arr);//Display "a,b,0,1,2,3,4,5,6"
arr=[0,1,2,3,4 ,5,6];
arr.splice(3,2,"c","d");
document.write(arr);//Display "0,1,2,c,d, 5,6"
objArray.unshift(item1[,item2[,...]]]) ------------------- Insert the parameter list into the array beginning. Its nature is the same as the push method type, but the push method adds elements to the end of the array. For example: [1,2,3,4].unshift("a","b") will get ["a","b",1,2,3,4].
Bubble sorting method from largest to smallest:
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
