$ ./expense clear
This will remove all expenses. Are you sure? (y/n)

From: /Users/wangxuefei/Documents/launchschool/180/4/expense/expense @ line 51 ExpenseData#clear_expenses:

    47: def clear_expenses
    48:   puts "This will remove all expenses. Are you sure? (y/n)"
    49:   answer = nil
    50:   loop do
 => 51:     binding.pry
    52:     answer = gets.chomp.to_s.downcase
    53:     break if %(y n).include? answer
    54:     puts "You must press 'y' or 'n'."
    55:   end
    56:
    57:   return if answer == 'n'
    58:
    59:   sql = "DELETE FROM expenses;"
    60:   @connection.exec(sql)
    61:   puts "All expenses have been deleted."
    62: end

[1] pry(#<ExpenseData>)> answer = gets.chomp.to_s.downcase
Errno::ENOENT: No such file or directory @ rb_sysopen - clear
from (pry):1:in `gets'
[2] pry(#<ExpenseData>)> require 'io/console'
=> false

刚开始学数据库

请教下各位朋友 这里为什么 gets 用不了啊，想用 getch, 可是 require 'io/console'又不好使。 但是在 irb 下，prompt 这个代码是能正常运行的

另外这个问题该用什么有效的英文关键字在 google 搜索答案呢？搞了半天也找到。