


JavaScript obtains a simple example of the intersection of multiple arrays_javascript skills
In the project, it is necessary to obtain the intersection of multiple arrays, so this example is only suitable for specific scenarios. For example, A array var a = {1000,10001,10002,10003}; B array var b = {10002, 10003}; C array var c = {10003}; You need to obtain the intersection array of these three arrays.
The specific idea is: first initialize the smallest array as the A array, and the smallest number of elements is also the length of the array A. Then iterate through each array, obtain the shortest length of these arrays as the minimum length, and at the same time obtain the shortest length array . Then, iterate the minimum array and each array, start to compare the elements for equality, and use a counter to determine whether the element exists in each array and it is an intersection element.
The idea is relatively simple, but it can be achieved to obtain intersection with multiple arrays. The code is as follows:
<script> <BR> function getValues(obj){ <BR> var values = ""; <BR> var l = obj.options.length; <BR> for (var i=0; i<l; i ) { <BR> if (i != (l-1)) { <BR> values = obj.options(i).value "_"; <BR> } <BR> else { <BR> values = obj.options(i).value; <BR> } <BR> } <BR> return values; <BR> } <br><br> function _test() { <BR> var ids = getValues(document.all.aa); <BR> var aa = _getIntersection(ids); <BR> } <br><br> function _getIntersection(src) { <BR> var tAry = src.split("_"); <BR> //最小数组 <BR> var minAry = null; <BR> var min = tAry[0].split(",").length; //初始化第一个为长度最小的数组 <BR> minAry = tAry[0].split(","); <BR> for (var i = 1, len = tAry.length; i<len; i ) { <BR> var temp = tAry[i].split(","); <BR> if (temp.length < min) { <BR> min = temp.length; <BR> minAry = temp; <BR> } <BR> }<BR> alert("最小数组:" minAry); <br><br> var ret = ''; <BR> for (var i = 0, len = minAry.length; i<len; i ) { <BR> var srcNum = parseInt(minAry[i]); <BR> var counter = 0; <BR> for (var j = 0, ll = tAry.length; j<ll; j ) { <BR> var tt = tAry[j].split(","); <BR> for (var k = 0, l = tt.length; k<l; k ) { <BR> var tarNum = parseInt(tt[k]); <BR> if (srcNum == tarNum) { <BR> counter ; <BR> } <BR> } <BR> } <BR> if (counter == tAry.length) { <BR> ret = srcNum ","; <BR> } <BR> } <BR> ret = strSlice(ret, ','); <BR> alert("交集是:" ret); <BR> } <br><br> //去掉结尾分隔符 <BR> function strSlice(str, split){ <BR> if ((str!=null && str!="") && (split!=' ')) <BR> return ((str.charAt(str.length-1) == split) ? str.substring(0, str.length-1) : str); <BR> else <BR> return str; <BR> } <BR> </script>

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