Question

当我的一个提示在下面的代码中留空时，我试图缩短返回“NO ANSWER”的代码：

var name = prompt("What is your name?");
var age = prompt("What is your age?");
var address = prompt("What is your email address?");
var credit = prompt("What is your credit card number?");
var social = prompt("What is your social security number?");

var arr = [name, age, address, credit, social];
var l = arr.length;

for (var i = 0; i < l; i++) {

  if (arr[i] == "") {

    arr[i] = "NO ANSWER";

  }

}

alert("Your information is " + name + ", " + age + ", " + address + ", "    + credit + ",  and" + social + ".");
alert("Now the internet has all of your information. Have a nice day >:D");

但是，代码不起作用。谁能告诉我为什么？

Answer 1

for循环确实有效并按预期工作。打印或使用这些输入变量时，需要使用数组arr。那是因为当你执行arr[i] = "NO ANSWER";时，实际上是将数组元素设置为“NO ANSWER”，而不是原始变量。请参阅以下内容：

var name = prompt("What is your name?");
var age = prompt("What is your age?");
var address = prompt("What is your email address?");
var credit = prompt("What is your credit card number?");
var social = prompt("What is your social security number?");

var arr = [name, age, address, credit, social];
var l = arr.length;

for (var i = 0; i < l; i++) {

  if (arr[i] == "") {

    arr[i] = "NO ANSWER";

  }

}

alert("Your information is " + arr[0] + ", " + arr[1] + ", " + arr[2] + ", "    + arr[3] + ",  and" + arr[4] + ".");
alert("Now the internet has all of your information. Have a nice day >:D");

Answer 2

试试这个。您似乎正在更新arr，但您没有在屏幕上打印arr。

var name = prompt("What is your name?");
var age = prompt("What is your age?");
var address = prompt("What is your email address?");
var credit = prompt("What is your credit card number?");
var social = prompt("What is your social security number?");

var arr = [name, age, address, credit, social];
var l = arr.length;

for (var i = 0; i < l; i++) {
  if (arr[i] == "") {
    arr[i] = "NO ANSWER";
  }
}

alert("Your information is " + arr[0] + ", " + arr[1] + ", " + arr[2] + ", "    + arr[3] + ",  and " + arr[4] + ".");

Answer 3

我试着干运行没有地址的代码。以下代码有效。 if语句需要更改

testarr = function () {
var name = 'xxx';
var age = 10;
var address;
var credit = 252525;
var social = 564654;
var arr = [name, age, address, credit, social];
var l = arr.length;

for (var i = 0; i < l; i++) {
  if (!arr[i]) {
    arr[i] = "NO ANSWER";
  }
}

return arr;
//alert("Your information is " + name + ", " + age + ", " + address + ", "    + credit + ",  and" + social + ".");
//alert("Now the internet has all of your information. Have a nice day >:D");
}

var t = new testarr();
console.log ("Your information is " + t[0] + ", " + t[1] + ", " + t[2] + ", "    + t[3] + ",  and" + t[4] + ".")

我的for循环不起作用

3 个答案: