如何通过仅使用数组方法计算JavaScript中数组的双精度值
[英]How to Count a Double Value Of Array In JavaScript By Using Just Array Methods
问题描述
嗨，您好，
我被赋予了一项任务：
到目前为止，这是我尝试过的：
var myArray = [1, 5, 1, 1, 5, 2, 4, 5, 2, 3, 2, 4, 2, 4, 2, 3, 2, 3, 2, 4, 2, 3, 2, 4, 2, 5, 1, 4, 2, 4, 2, 3, 2, 4, 1, 1, 5, 1, 1, 5, 2, 4, 5, 2, 3, 2, 4, 2, 4, 2, 3, 2, 3, 2, 4, 2, 3, 2, 4, 2, 5, 1, 4, 2, 4, 2, 3, 2, 4, 1, 1, 5, 1, 1, 5, 2, 4, 5, 2, 3, 2, 4, 2, 4, 2, 3, 2, 3, 2, 4, 2, 3, 2, 4, 2, 5, 1, 4, 2, 4, 2, 3, 2, 4, 1]; document.writeln("myArray elements<br/>"); document.writeln(myArray + "<br/>"); document.writeln("myArray has " + myArray.length + " elements" + "<br/>"); document.writeln("My Array sorted: <br/>"); myArray.sort(function(a, b) { return a - b });; document.writeln(myArray + "<br/>"); document.writeln("First Occurrence of number " + "?" + " in myArray Sorted is at index: " + myArray.indexOf(1) + "<br/>"); document.writeln("First Occurrence of number " + "?" + " in myArray Sorted is at index: " + myArray.indexOf(2) + "<br/>"); document.writeln("First Occurrence of number " + "?" + " in myArray Sorted is at index: " + myArray.indexOf(3) + "<br/>"); document.writeln("First Occurrence of number " + "?" + " in myArray Sorted is at index: " + myArray.indexOf(4) + "<br/>"); document.writeln("First Occurrence of number " + "?" + " in myArray Sorted is at index: " + myArray.indexOf(5) + "<br/>"); document.writeln("myArray contains " + "?" + " occurrence of number " + "?" + "<br/>"); document.writeln("myArray contains " + "?" + " occurrence of number " + "?" + "<br/>"); document.writeln("myArray contains " + "?" + " occurrence of number " + "?" + "<br/>"); document.writeln("myArray contains " + "?" + " occurrence of number " + "?" + "<br/>"); document.writeln("myArray contains " + "?" + " occurrence of number " + "?" + "<br/>");
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Task 2 with Arrays</title> </head> <body> <h1>Task 2 with Arrays</h1> </body> </html>
哪里： ？ 标记是我卡住的地方。
我只能使用：
- 长度属性，
- 的toString（）
- 分类（）
- 指数（）
请注意没有循环，允许条件语句。
拜托，有人可以帮我吗？
谢谢
3 个解决方案
解决方案1
1 2018-02-13 21:09:30
var myArray = [1, 5, 1, 1, 5, 2, 4, 5, 2, 3, 2, 4, 2, 4, 2, 3, 2, 3, 2, 4, 2, 3, 2, 4, 2, 5, 1, 4, 2, 4, 2, 3, 2, 4, 1, 1, 5, 1, 1, 5, 2, 4, 5, 2, 3, 2, 4, 2, 4, 2, 3, 2, 3, 2, 4, 2, 3, 2, 4, 2, 5, 1, 4, 2, 4, 2, 3, 2, 4, 1, 1, 5, 1, 1, 5, 2, 4, 5, 2, 3, 2, 4, 2, 4, 2, 3, 2, 3, 2, 4, 2, 3, 2, 4, 2, 5, 1, 4, 2, 4, 2, 3, 2, 4, 1]; document.writeln("myArray elements<br/>"); document.writeln(myArray + "<br/>"); document.writeln("myArray has " + myArray.length + " elements" + "<br/>"); document.writeln("My Array sorted: <br/>"); myArray.sort(function(a, b) { return a - b });; document.writeln(myArray + "<br/>"); document.writeln("First Occurrence of number " + "1" + " in myArray Sorted is at index: " + myArray.indexOf(1) + "<br/>"); document.writeln("First Occurrence of number " + "2" + " in myArray Sorted is at index: " + myArray.indexOf(2) + "<br/>"); document.writeln("First Occurrence of number " + "3" + " in myArray Sorted is at index: " + myArray.indexOf(3) + "<br/>"); document.writeln("First Occurrence of number " + "4" + " in myArray Sorted is at index: " + myArray.indexOf(4) + "<br/>"); document.writeln("First Occurrence of number " + "5" + " in myArray Sorted is at index: " + myArray.indexOf(5) + "<br/>"); document.writeln("myArray contains " + (myArray.indexOf(2)-myArray.indexOf(1)) + " occurrence of number " + 1 + "<br/>"); document.writeln("myArray contains " + (myArray.indexOf(3)-myArray.indexOf(2)) + " occurrence of number " + 2 + "<br/>"); document.writeln("myArray contains " + (myArray.indexOf(4)-myArray.indexOf(3)) + " occurrence of number " + 3 + "<br/>"); document.writeln("myArray contains " + (myArray.indexOf(5)-myArray.indexOf(4)) + " occurrence of number " + 4 + "<br/>"); document.writeln("myArray contains " + (myArray.length-myArray.indexOf(5)) + " occurrence of number " + 5 + "<br/>");
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Task 2 with Arrays</title> </head> <body> <h1>Task 2 with Arrays</h1> </body> </html>
解决方案2
0 2018-02-13 21:04:25
提示：如果数组正确排序，则第一个出现的2将计数所有1。
myArray.indexOf(2) - myArray.indexOf(1)
正在计算所有出现的1。
只需做一些简单的数学运算即可找出其他数字的位置和数目。
使用给定的工具，我认为没有一种方法可以动态地找到数组中的所有唯一数字，您需要对其进行硬编码。
解决方案3
0 2018-02-13 21:12:40
您是排序数组中所有数字的第一个匹配项。 因此，您可以进行简单的减法运算以获得两个相邻数字的首次出现索引之间的差。
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