无法解决“传递的参数无效”答案

【问题标题】：Can't solve 'Invalid arguments passed'无法解决“传递的参数无效”
【发布时间】：2017-06-10 11:31:03
【问题描述】：

为什么会出现这个错误？

警告：implode()：在第 17 行的 /Applications/XAMPP/xamppfiles/htdocs/basis/php/php.php 中传递的参数无效

index.php:

<?php


require_once 'php.php';
$piet = new Persoon();
$piet->voornaam = 'Piet';
$piet->achternaam = 'Jansen';
echo "De naam is: " . $piet->showNaam();

$piet->addHobby('zeilen');
$piet->addHobby('hardlopen');
echo "<br/> De hobbies van {$piet->showNaam()} zijn: {$piet->showHobbies()}";

?>

php.php

<?php
    class Persoon {
        public $voornaam = '';
        public $achternaam = '';
        protected $adres;
        protected $hobbies;

        public function showNaam() {
            return $this->voornaam . ' ' . $this->achternaam;
        }

        public function addHobby($hobby) {
            $hobbies[] = $hobby;
        }

        public function showHobbies() {
            echo implode(', ', $this->hobbies);
        }
    }

?>

【问题讨论】：

implode 第二个参数应该是数组所以改变这一行 $this->hobbies[] = $hobby;

标签： php

【解决方案1】：

在addHobby() 方法中，您必须使用$this->hobbies 而不是$hobbies。最好用空数组初始化hobbies，防止出错。

<?php
    class Persoon {
        public $voornaam = '';
        public $achternaam = '';
        protected $adres;
        protected $hobbies = array();

        public function showNaam() {
            return $this->voornaam . ' ' . $this->achternaam;
        }

        public function addHobby($hobby) {
            $this->hobbies[] = $hobby;
        }

        public function showHobbies() {
            echo implode(', ', $this->hobbies);
        }
    }

?>

【讨论】：

【解决方案2】：

变量访问是错误的。

<?php
class Persoon {
    public $voornaam = '';
    public $achternaam = '';
    protected $adres;
    protected $hobbies;

    public function showNaam() {
        return $this->voornaam . ' ' . $this->achternaam;
    }

    public function addHobby($hobby) {
        $this->hobbies[] = $hobby; <--- change this
    }

    public function showHobbies() {
        //echo implode(', ', $this->hobbies);// remove this
        echo count($this->hobbies) ? implode(', ', $this->hobbies) : "";// this will avoid errors in future if your array is empty.
    }
}

?>

【讨论】：

【解决方案3】：

每次调用 addHobby($hobby) 函数时，您的代码都会创建一个新数组，您需要做的是正确访问它。改变

public function addHobby($hobby) {
            $hobbies[] = $hobby;
        }

到

 public function addHobby($hobby) {
            $this->hobbies[] = $hobby;

        }

【讨论】：