我有一个名为Family Members的类（在文件family_members.rb中），其中包含name，sex，type，{{等属性1}}和role。
我创建了名为age，fm1 fm2 fm3和fm4的实例。
fm5我有一个名为#family_members.rb
require_relative 'family'
require_relative 'checkdetails'
class FamilyMembers < Family
attr_accessor :name, :sex, :status, :age
def initialize (name, sex, type, role, age)
@name = name
@sex = sex
@type = type
@role = role
@age = age
end
end
fm1 = FamilyMembers.new('Andrew','Male', 'Child', "Son" , "27" )
fm2 = FamilyMembers.new("Bill","Male", "Parent", "Father" , "63" )
fm3 = FamilyMembers.new("Samantha","Female", "Parent", "Mother" , "62" )
fm4 = FamilyMembers.new("Thomas","Male", "Child", "Dog" , "10" )
fm5 = FamilyMembers.new("Samantha", 'Female', "Child", "Dog" , "4" )
的方法，用于检查该类的实例是Parent?还是Parent，并且调用如下所示：
Child用户是否可以动态选择要检查的类的哪个实例？
我在#check_details //would like to use this method
fm4.parent?
文件中创建了一个名为check_details的方法：
checkdetails.rb但是，如果我尝试像这样调用#checkdetails.rb
def check_details
puts "What family to you want to check? choose 1 to 5"
$family = 'fm' + gets.chomp
end
方法：
parent它给了我以下错误：
check_details
$family.parent?
有没有办法动态地执行此操作？可能没有全局变量 - 因为这被认为是不好的做法？
感谢您的帮助。
答案 0 :(得分：0)
将您的FamilyMembers存储在数组或哈希中，然后按键查找。
fm = {}
fm[1] FamilyMembers.new('Andrew','Male', 'Child', "Son" , "27" )
fm[2] = FamilyMembers.new("Bill","Male", "Parent", "Father" , "63" )
fm[3] = FamilyMembers.new("Samantha","Female", "Parent", "Mother" , "62" )
fm[4] = FamilyMembers.new("Thomas","Male", "Child", "Dog" , "10" )
fm[5] = FamilyMembers.new("Samantha", 'Female', "Child", "Dog" , "4" )
answer = "3" # get this from the user.
num = answer.to_i
if fm.key?(num)
fm[num].parent?
else
raise 'Invalid answer'
end
P.S。 Ruby指南建议将“FamilyMembers”类称为“FamilyMember”。