在Ruby對象類中創建一個數組

Question

我只想寫一個包含一個ID數組的類的Ruby腳本（無欄）。這是我的原班：

# define a "Person" class to represent the three expected columns 
class Person < 

    # a Person has a first name, last name, and city 
    Struct.new(:first_name, :last_name, :city) 

    # a method to print out a csv record for the current Person. 
    # note that you can easily re-arrange columns here, if desired. 
    # also note that this method compensates for blank fields. 
    def print_csv_record 
    last_name.length==0 ? printf(",") : printf("\"%s\",", last_name) 
    first_name.length==0 ? printf(",") : printf("\"%s\",", first_name) 
    city.length==0 ? printf("") : printf("\"%s\"", city) 
    printf("\n") 
    end 
end 

現在我想一個數組叫ID添加到類，我可以將其包含在Struct.new聲明像Struct.new（：FIRST_NAME，：姓氏，：城市，：ids = Array.new）或創建一個實例數組變量或任何定義單獨的方法或別的東西？

我想那麼能夠做這樣的事情：

p = Person.new 
p.last_name = "Jim" 
p.first_name = "Plucket" 
p.city = "San Diego" 

#now add things to the array in the object 
p.ids.push("1") 
p.ids.push("55") 

和遍歷數組

p.ids.each do |i| 
    puts i 
end 

Answer 1

# define a "Person" class to represent the three expected columns 
class Person 
attr_accessor :first_name,:last_name,:city ,:ids 
# Struct.new(:first_name, :last_name, :city ,:ids) #used attr_accessor instead can be used this too 

def initialize 
    self.ids = [] # on object creation initialize this to an array 
end 
    # a method to print out a csv record for the current Person. 
    # note that you can easily re-arrange columns here, if desired. 
    # also note that this method compensates for blank fields. 
    def print_csv_record 
    print last_name.empty? ? "," : "\"#{last_name}\"," 
    print first_name.empty? ? "," : "\"#{first_name}\"," 
    print city.empty? ? "" : "\"#{city}\"," 
    p "\n" 
    end 
end 

p = Person.new 
p.last_name = "" 
p.first_name = "Plucket" 
p.city = "San Diego" 

#now add things to the array in the object 
p.ids.push("1") 
p.ids.push("55") 

#iterate 
p.ids.each do |i| 
    puts i 
end 

Answer 2

在假設我知道你想要什麼，它是這麼簡單。添加到您的Person類：

def initialize(*) 
    super 
    self.ids = [] 
end