ruby中格式字符串的用途是什么

Question

formatter = "%{first} %{second} %{third} %{fourth}"

puts formatter % {first: 1, second: 2, third: 3, fourth: 4}

puts formatter % {first: "one", second: "two", third: "three", fourth: "four"}

puts formatter % {first: true, second: false, third: true, fourth: false}

puts formatter % {first: formatter, second: formatter, third: formatter, fourth: formatter}

puts formatter % {
  first: "I had this thing.",
  second: "That you could type up right.",
  third: "But it didn't sing.",
  fourth: "So I said goodnight."
}

我很担心你会在ruby中使用格式字符串，有人可以解释一下。感谢

Answer 1

在伪代码中：

MAIL_TEMPLATE = <<-TMPL
Hello, %{name}!

The support for %{product} will be ended at %{date} unless
due to insufficient amount of money on your account %{account}.

The amount to pay to continue using %{product}: %{debt}
TMPL

Storage.all_users.map(&:to_hash).each |user|
  send_email(user.delete[:email], MAIL_TEMPLATE % user) if user[:debt]
end

以上内容可用于向帐户中没有足够金额的用户发送电子邮件。请注意，除了电子邮件模板外，还有2LOC。

请参阅以下@ mu-is-too-short的非常有价值的评论。