JavaScript gets the intersection of multiple arrays
高洛峰
Release: 2016-11-25 13:23:08
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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 is the intersection element. The idea is relatively simple, but it can be achieved to obtain intersection with multiple arrays. The code is as follows:
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<script> <br> function getValues(obj){ <br> var values = ""; var l = obj.options.length; <br> for (var i=0; i<l; i++) { <br/> <br/> values += obj.options(i).value ; <br/> (document.all.aa); <br/> var aa = _getIntersection(ids); <br/> var tAry = src.split("_"); <br/> using using using using out out through through using off ‐ ‐ ‐ ‐ tAry to src.split("_"); length The smallest array <br/> using using using using using using using using through using through ’ s ‐ to ‐ ‐ ‐‐ ‐ minAry = tAry[0].split(","); <br/> ","); <br/> <br/> ‐‐‐ ‐‐ ‐‐ ‐ ‐ ‐ ‐ alert ("Minimum array: "+minAry); 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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