Question

我正在尝试在此示例中将原型添加到已创建的对象实例（Person1），但它未成功添加，从而产生错误。有人可以帮我吗？

import pandas as pd
import datetime as dt

date=dt.date(2018,1,18)
purchase_1 = pd.Series({'Store':'Store 1','Date': date,
                        'Item Purchased': 'Dog Food',
                        'Cost': 22.50,'Client':'Mark'})
purchase_2 = pd.Series({'Store':'Store 2','Date': date,
                        'Item Purchased': 'Kitty Litter',
                        'Cost': 2.50,'Client':'Den'})
purchase_3 = pd.Series({'Store':'Store 3','Date': date,
                        'Item Purchased': 'Bird Seed',
                        'Cost': 5.00,'Client':'Max'})


df = pd.DataFrame([purchase_1, purchase_2, purchase_3])
df = df.set_index(['Store', 'Date'])
df.index.names = ['Store', 'Date']


Store   Date        Client Cost   Item Purchased
Store 1 2018-01-18  Mark   22.5   Dog Food
Store 2 2018-01-18  Den    2.5    Kitty Litter
Store 3 2018-01-18  Max    5.0    Bird Seed

Answer 1

问题是person是一个函数而person1是一个对象。使用constructor.prototype解决问题。

＆＃13;

<html> 
<head></head>
<body>

<script>

var person = function(name, age){
this.name = name;
this.age = age; 
this.printName = function(){
    alert(this.name);
}
}
person.prototype.printAge = function(){
alert(this.age);
}

var person1 = new person("Jack", 29); 
person1.constructor.prototype.printMessage = function(){
alert("Hello Friend"); 
}

var person2 = Object.create(person1);
person2.printName();
person2.printAge();
person2.printMessage();

</script>

</body>
</html>

＆＃13;

Answer 2

只有构造函数具有protoype属性（通过this.propertyName设置属性值的函数。虽然你可以使用

__proto__

它被认为效率低下。

检查一下。

stackoverflow reference

将原型添加到对象是错误的

2 个答案: