In Ruby I have this csv file:

make,model,color,doors,email
dodge,charger,black,4,[email protected]
ford,focus,blue,5,[email protected]
nissan,350z,black,2,[email protected]
mazda,miata,white,2,[email protected]
honda,civid,brown,4,[email protected]
corvette,stingray,red,2,[email protected]
ford,fiesta,blue,5,[email protected]
bmw,m4,black,2,[email protected]
audi,a5,blue,2,[email protected]
subaru,brz,black,2,[email protected]
lexus,rc,black,2,[email protected]

and this is my code:

def delete_from_data
    print "\nTo delete a car, enter the email (this is case sensitive): \n> "
    delete_car = gets.chomp

    #this allows me to delete a certain row based on email
    table = CSV.table("cars.csv")
    table.delete_if do |row|
        row[:email] == delete_car
    end
    File.open("cars.csv", "w") do |f|
        f.write(table.to_csv)
    end

    #this shows the updated student roster after deleting user
    puts "\nThis is the updated roster after deleting: #{delete_car}"
end

Having this code, how can I make it if the user enters an invalid email (misspelled email or anything that doesn't match an email from the CSV file), it asks to enter a valid one since the one they typed isn't an email from the CSV file

CodePudding user response：

Load table first.

Now you can use #any? to see if any rows contain that email address.

table.any? { |row| row["email"] == delete_car }

Now, just do this in a loop, breaking the loop when the input email address is in the table.

delete_car = loop do
  email = gets.chomp
  break email if table.any? { |row| row["email"] == email }
  puts "Invalid input. Try again."
end

You may also wish to generate a set of valid email addresses. If you think you'll need to loop several times, this may lead to better performance.

valid_emails = table.map { |row| row["email"] }.to_set

delete_car = loop do
  email = gets.chomp
  break email if valid_emails.include?(email)
  puts "Invalid input. Try again."
end