Read the catalogue:
- DS01: Three ways to find duplicate elements in a common array
- DS02: A collection of commonly used JS functions
three ways to find duplicate elements in an array, commonly used in DS01
1.
1 varary =NewArray ("111", "22", "33", "111"); 2 vars = Ary.join (",") + ","; 3 for(vari=0;i<ary.length;i++) { 4 if(S.replace (ary[i]+ ",", ""). IndexOf (ary[i]+ ",") >-1) { 5Alert ("There are repeating elements in the array:" +Ary[i]); 6 Break; 7 }8}
2.
1 var New Array ("111", "a", "" "," 111 "); 2 var nary=Ary.sort (); 3 for (var i=0;i<ary.length;i++) { 4 if (nary[i]==nary[i+1 ] { 5 alert ("There are repeating elements in the array:" +nary[i]) ; 6 } 7 }
3.
1 functionIsrepeat (arr) {2 varhash = {}; 3 for(varIincharr) { 4 if(Hash[arr[i]])5 return true; 6Hash[arr[i]] =true; 7 } 8 return false; 9}
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DS02: A collection of commonly used JS functions
1. Pop method
Function: Removes the last element in the array and returns the element.
Example: Arrayobj.pop ()Description:The required arrayobj reference is an Array object.
if the array is empty, then the undefined is returned.
2. Push Method
Function: Adds a new element to an array and returns the new length value of the array.
Example: Arrayobj.push ([item1 [item2 [...] [Itemn]])
Parameters:
Arrayobj, Required option, an Array object.
Item, Item2,... itemn options available. Represents the new element of the Array. return value: The new length value of the array.
3.
Unshift Method
Function: Inserts the specified element into the starting position of the array and returns the array.
Example: Arrayobj.unshift ([item1[, item2 [, ...] [, Itemn]]])
Parameters:
Arrayobj, Required option, an Array object.
Item1, item2,.. ., Itemn, optionally, the element that will be inserted into the beginning part of the Array.
Description
The Unshift method inserts these elements into the beginning of an array, so the elements appear in the array in the order in which they are in the parameter sequence.
return value: the current array.
4. Splice Method
Function: Removes one or more elements from an array and, if necessary, inserts a new element at the location of the removed element, returning the element that was removed.
Example: Arrayobj.splice (Start, DeleteCount, [item1[, item2[, ... [, Itemn]]])
Parameters:
Arrayobj, Required option, an Array object.
Start, required option, specifies the starting position of the element to be removed from the array, which is calculated starting at 0.
DeleteCount, required option, the number of elements to remove.
Item1, item2,.. ., itemn, a mandatory option to insert a new element at the location of the removed element.
Description
The splice method modifies the Arrayobj by removing the specified number of elements from the start position and inserting the new element. return value: is a new Array object consisting of the removed elements.
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19:38:09 2015-01-15
by Selonsy
(Pending update)
JS Array Common functions and find out if there are duplicate elements in the array three common methods
