[js] 处理二维数组
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1 //按列访问 2 var grades = [ 3 [89, 77, 78], 4 [76, 82, 81], 5 [91, 94, 89] 6 ]; 7 var total = 0; 8 var average = 0.0; 9 for (var row = 0; row < grades.length; ++row) { 10 for (var col = 0; col < grades[row].length; ++col) { 11 total += grades[row][col]; //行不变，列变，可处理参差不齐的数组 12 } 13 average = total / grades[row].length; 14 console.log("Student " + parseInt(row + 1) + " average: " + 15 average.toFixed(2)); 16 total = 0; 17 average = 0.0; 18 } 19 //按行访问 20 var grades = [ 21 [89, 77, 78], 22 [76, 82, 81], 23 [91, 94, 89] 24 ]; 25 var total = 0; 26 var average = 0.0; 27 for (var col = 0; col < grades.length; ++col) { 28 for (var row = 0; row < grades[col].length; ++row) { 29 total += grades[row][col]; //行变，列不变 30 } 31 average = total / grades[col].length; 32 console.log("Test " + parseInt(col + 1) + " average: " + 33 average.toFixed(2)); 34 total = 0; 35 average = 0.0; 36 } 37 //对象数组 38 function Point(x, y) { 39 this.x = x; 40 this.y = y; 41 } 42 43 function displayPts(arr) { 44 for (var i = 0; i < arr.length; ++i) { 45 console.log(arr[i].x + ", " + arr[i].y); 46 } 47 } 48 var p1 = new Point(1, 2); 49 var p2 = new Point(3, 5); 50 var p3 = new Point(2, 8); 51 var p4 = new Point(4, 4); 52 var points = [p1, p2, p3, p4]; 53 for (var i = 0; i < points.length; ++i) { 54 console.log("Point " + parseInt(i + 1) + ": " + points[i].x + ", " + 55 points[i].y); 56 } 57 var p5 = new Point(12, -3); 58 console.log(p5); //Point {x: 12, y: -3} 59 points.push(p5); 60 displayPts(points); 61 points.shift(); 62 displayPts(points);
