Several important methods of the 2016-06-06 array

1.

var arr=[1,2,3]arr.push (' abc '); // returns the length of the array is 4 arr=[1,2,3, ' abc '] if it is Arr.unshift (' abc '), and the returned array length is 4,IE6 IE7 does not support return is undefined,arr=[' abc ', ]var arr=[1,2,3];arr.pop (); Delete the last arr=[1,2], Arr.pop () returns the deleted element Arr.shift (); Delete the first Arr=[2,3] Swap location var arr =[' A ', ' B ', ' C ', ' d ']; requirements: A b C moves backward one, d on the top of the resolution: First Take D away Arr.pop (); // The return is D, then place to the first bit  arr.unshift (Arr.pop ()); Request: b c D move forward a bit to the last solution: take a away namely: Arr.shift (), put a in the last Arr.push () Arr.push ( Arr.shift ());

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    //Splice method for hanging and frying days remove replace add function    varArr =[' A ', ' B ', ' C ', ' d ', ' e ']; //DeleteAlert (Arr.splice (0,2));//returned is the deletion of something, starting from the No. 0 bit to delete two bits namely a BAlert (arr);//arr=[c,d,e    //ReplaceAlert (Arr.splice (0,1, ' FFF '));//replacing the No. 0 bit of the array is a, replacing only one bit, so eject aAlert (arr);//fff,b,c,d,eAlert ((Arr.splice (0,2, ' FFF ', ' GGG '))//A B starts with the 0th position, replaces the two bit, and if GGG is not written, the array length is reduced by one bitAlert (arr)//fff,ggg,c,d,e    //AddAlert (Arr.splice (1,0, ' m ', ' n ', ' l '));//add three numbers from where the array is labeled 1, and 0 for addAlert (arr)//a M n l b c d e    //Go heavy    vararr=[1,1,2,2,2,4,4,4,6,4,5,8,8]; Alert (Removerepeat (arr));//1 2 4 6 5 8    //method of extracting the weight    functionRemoverepeat (arr) {if(arr==NULL|| arr==undefined)return;  for(vari=0;i<arr.length;i++){             for(varj=i+1; j<arr.length;j++){                if(arr[i]==Arr[j]) {Arr.splice (J,1);//Note that if you delete the small Mark J, the array length will be reduced by 1j--;//so the elements of arr[j] also need to be reduced by one                }            }        }        returnarr; }    //sort () sorting    //1. The default sort () order is a string comparison, only the first digit is compared    varNums =[1,4,7,8,5,9]; Alert (Nums.sort ());//1 4 5 7 8 9    varChars=[' A ', ' Z ', ' C ', ' f ', ' t ']//a C f t z because a-Z 97-122alert (Chars.sort ()); varNUMS2=[1,4,22,3,8,9,77,56,48];//-->var nums2=[' 1 ', ' 4 ', ' 22 ', ' 3 ', ' 8 ', ' 9 ', ' 77 ', ' 56 ', ' 48 '] ' 77 ' first bit is 7, less than 8 and 9Alert (Nums2.sort ());//1 22 3 4 48 56 77 8 9 Why is this??? because the default sort () sort is a string comparison and only compares the first bit    //How to change this situation, add comparatorAlert (Nums2.sort (function(A, B) {returnA-B;}));//1 3 4 8 9    //How to sort strings is not exactly a number ?    varArr =[' 100px ', ' 20px ', ' 8px ', ' 10px ', ' 200px ']; //alert (Arr.sort ())//default is 100px 10px 200px 20px 8px    //What do you do? Remove Ox and add comparatorAlert (Arr.sort (function(A, B) {returnparseint (a)-parseint (b)));//8px 10px 20px 100px 200px</script>

3. Random number

    Random number    //0-x    math.round (Math.random () *x);    1-x    Math.ceil (Math.random () *x);    Random numbers from X to Y  such as: 100-450    Math.Round (Math.random () * (y-x) +x);

4. Flipping a string

The array is converted into a string with the join ()    var str= ' ABCDEFG ';    var arr=str.split (');    Alert (Arr.reverse (). Join ('));

　　

　　

Several important methods of the 2016-06-06 array