创建一个检查对象的函数答案

【问题标题】：Creating a function that checks objects创建一个检查对象的函数
【发布时间】：2021-02-26 00:02:09
【问题描述】：

我无法创建一个检查数组中对象的函数。它需要检查年份是否为 2018 年或更早，如果是，我需要输出它。我尝试了一些我认为可以像这样工作的更简单的方法：

function checkQualifies(year){
    year >= 2018
  };

和function checkQualifies(item, index){ if(carTypes) { printCarTypes(carTypes.filter(x=>x.year>="2018")) } } 但它要么破坏我的代码，要么无法运行。这是我的全部代码：

<html>
<head>
  <title>Assignment Seven : Array, Objects, Functions, Methods</title>
  <meta author="My Name" />
</head>
<body>
  <h1>Javascript Assignment</h1>

  <br/>

  <h2>Your Output</h2>

  <div id="my_output"></div>


</body>
</html>

<script>

  var studentName = "Alicia Villatoro";

  writeToPage("Assignment for: " + studentName);
  writeToPage("");

  writeToPage("Program 1: Writing an Array of Car Makes");
  writeToPage("");

  writeToPage("Creating Array: ");

  var array_name = car_makes;
  var car_makes = ["Toyota", " Honda", " Audi", " BMW", " Mercedes"];

  writeToPage("Displaying Array: ");

  writeToPage(car_makes);

  writeToPage("Program 2");
  writeToPage("");

  writeToPage("Create Car Object: ");

  var toyotaCamryCar = new Object();
  toyotaCamryCar['make'] = "Toyota";
  toyotaCamryCar['model'] = "Camry";
  toyotaCamryCar['year'] = "2019";
  toyotaCamryCar['price'] = 25000;

  writeToPage("Write the Car Object and Attributes");

  writeToPage(toyotaCamryCar['make']);
  writeToPage(toyotaCamryCar['model']);
  writeToPage(toyotaCamryCar['year']);
  writeToPage(toyotaCamryCar['price']);

  writeToPage("Program 3");
  writeToPage("");

  writeToPage("Create an Array of Objects");

  var carTypes = [];
  carTypes.push({make:"Toyota", model: "Camry", year: "2018"});
  carTypes.push({make: "Toyota", model: "Corolla", year: "2019"});
  carTypes.push({make: "Audi", model: "A4", year: "2017"});
  carTypes.push({make: "BMW", model: "i3", year: "2018"});
  carTypes.push({make: "Honda", model :"Accord", year: "2016"});

  writeToPage("Displaying Objects: ");

  printCarTypes(carTypes);

  writeToPage("Program 4");
  writeToPage("");

  writeToPage("Check the objects and print out the Toyota ones, use conditionals");

  if(carTypes){
    printCarTypes(carTypes.filter(x=>x.make==="Toyota"))
  };


  writeToPage("Program 5");
  writeToPage("");


  writeToPage("Create the checkQualifies function");

  function checkQualifies(item, index){
    if(carTypes)
    {
      printCarTypes(carTypes.filter(x=>x.year>="2018"))
    }
  }

  writeToPage("Run the checkQualifies below for each entry of the array from Program 3");


  writeToPage("Complete");


  function printCarTypes(carTypes) {
    for (var i = 0; i < carTypes.length; i++) {
      writeToPage("Car Types [" + i + "]: " + JSON.stringify(carTypes[i]));
    }
    writeToPage("");
  }
  function writeToPage(strText) {
    var output = document.getElementById("my_output");
    var currentValue = output.innerHTML;
    output.innerHTML = currentValue + "<br/>" + strText;
  }

</script>'

【问题讨论】：

标签： javascript arrays function object

【解决方案1】：

您忘记调用checkQualifies() 函数。我在 "Complete" 行之前调用了它，经过测试，它可以工作。

<html>
<head>
  <title>Assignment Seven : Array, Objects, Functions, Methods</title>
  <meta author="My Name" />
</head>
<body>
  <h1>Javascript Assignment</h1>

  <br/>

  <h2>Your Output</h2>

  <div id="my_output"></div>


</body>
</html>

<script>

  var studentName = "Alicia Villatoro";

  writeToPage("Assignment for: " + studentName);
  writeToPage("");

  writeToPage("Program 1: Writing an Array of Car Makes");
  writeToPage("");

  writeToPage("Creating Array: ");

  var array_name = car_makes;
  var car_makes = ["Toyota", " Honda", " Audi", " BMW", " Mercedes"];

  writeToPage("Displaying Array: ");

  writeToPage(car_makes);

  writeToPage("Program 2");
  writeToPage("");

  writeToPage("Create Car Object: ");

  var toyotaCamryCar = new Object();
  toyotaCamryCar['make'] = "Toyota";
  toyotaCamryCar['model'] = "Camry";
  toyotaCamryCar['year'] = "2019";
  toyotaCamryCar['price'] = 25000;

  writeToPage("Write the Car Object and Attributes");

  writeToPage(toyotaCamryCar['make']);
  writeToPage(toyotaCamryCar['model']);
  writeToPage(toyotaCamryCar['year']);
  writeToPage(toyotaCamryCar['price']);

  writeToPage("Program 3");
  writeToPage("");

  writeToPage("Create an Array of Objects");

  var carTypes = [];
  carTypes.push({make:"Toyota", model: "Camry", year: "2018"});
  carTypes.push({make: "Toyota", model: "Corolla", year: "2019"});
  carTypes.push({make: "Audi", model: "A4", year: "2017"});
  carTypes.push({make: "BMW", model: "i3", year: "2018"});
  carTypes.push({make: "Honda", model :"Accord", year: "2016"});

  writeToPage("Displaying Objects: ");

  printCarTypes(carTypes);

  writeToPage("Program 4");
  writeToPage("");

  writeToPage("Check the objects and print out the Toyota ones, use conditionals");

  if(carTypes){
    printCarTypes(carTypes.filter(x=>x.make==="Toyota"))
  };


  writeToPage("Program 5");
  writeToPage("");


  writeToPage("Create the checkQualifies function");

  function checkQualifies(item, index){
    if(carTypes)
    {
      printCarTypes(carTypes.filter(x=>x.year>="2018"))
    }
  }

  writeToPage("Run the checkQualifies below for each entry of the array from Program 3");
  checkQualifies()

  writeToPage("Complete");


  function printCarTypes(carTypes) {
    for (var i = 0; i < carTypes.length; i++) {
      writeToPage("Car Types [" + i + "]: " + JSON.stringify(carTypes[i]));
    }
    writeToPage("");
  }
  function writeToPage(strText) {
    var output = document.getElementById("my_output");
    var currentValue = output.innerHTML;
    output.innerHTML = currentValue + "<br/>" + strText;
  }

</script>

【讨论】：