javascript - 将值传递给 JavaScript 中的函数

Question

不知道为什么下面的代码不起作用。它应该接受一个字符串并将 G 转换为 C，将 A 转换为 T，反之亦然。然而，它收集输入字符串但不提供任何输出，即警报只是说“这是你的反向互补 DNA”

var dnaSequence = prompt("Enter your DNA sequence here", "");
var newSequence = reverseComplement(dnaSequence);
alert("here is your reverse complemented DNA: " + newSequence);

function reverseComplement(dnaString) {

    var reverseC = [];
    var dnaArr = dnaString.split('');

    for (var i = 0; i < dnaArr.length; i++) {

        switch (dnaArr[i]) {
            case 'A':
                reverseC.push('T');
                break;
            case 'T':
                reverseC.push('A');
                break;
            case 'C':
                reverseC.push('G');
                break;
            case 'G':
                reverseC.push('C');
                break;
        }
    }

    // Reverse and rejoin the the string    
    return reverseC.reverse().join('');
}

Answer 1

It should take in a string and convert a G to a C and an A to a T and vice versa.

那么你就不需要reverse()，因为你是按顺序推送的。

此外，请确保您在提示中输入大写字母。 否则，您可以强制使用大写。

这是包含两个修复的代码:

function reverseComplement(dnaString) {

    var reverseC = [];
    var dnaArr = dnaString.toUpperCase().split('');

    for (var i = 0; i < dnaArr.length; i++) {

        switch (dnaArr[i]) {
            case 'A':
                reverseC.push('T');
              break;
            case 'T':
                reverseC.push('A');
                break;
            case 'C':
                reverseC.push('G');
                break;
            case 'G':
                reverseC.push('C');
                break;
        }
    }

    // Reverse and rejoin the the string    
    return reverseC.join('');
}

var dnaSequence = prompt("Enter your DNA sequence here", "");
var newSequence = reverseComplement(dnaSequence);
alert("here is your reverse complemented DNA: " + newSequence);