1 從一種資料結構中構件字串
hash = { key1: "val1", key2: "val2" }
string = ""
hash.each { |k,v| string << "#{k} is #{v}\n" }
puts string
# key1 is val1
# key2 is val2
變種
string = "" hash.each { |k,v| string << k.to_s << " is " << v << "\n" }
更高效辦法使用 Array#join
puts hash.keys.join("\n") + "\n" # key1 # key2
或者
puts hash.keys.join("") # key1key2
2 建立一個包含ruby變數或者表示式的字串
number = 5 "The number is #{number}."# => "The number is 5." "The number is #{5}."# => "The number is 5." "The number after #{number} is #{number.next}."# => "The number after 5 is 6." "The number prior to #{number} is #{number-1}."# => "The number prior to 5 is 4." "We're ##{number}!"# => "We're #5!"
也可以這樣使用但不要這麼做
%{Here is #{class InstantClass
def bar
"some text"
end
end
InstantClass.new.bar
}.}
# => "Here is some text."
here document使用
name = "Mr. Lorum" email = <<END Dear #{name}, Unfortunately we cannot process your insurance claim at this time. This is because we are a bakery, not an insurance company. Signed, Nil, Null, and None Bakers to Her Majesty the Singleton END
# => "Dear Mr. Lorum,\nUnfortunately we cannot process your insurance claim at this\ntime. This is because we are a bakery, not an insurance company.\nSigned,\nNil, Null, and None\nBakers to Her Majesty the Singleton\n"
<<end_of_poem There once was a man from Peru Whose limericks stopped on line two end_of_poem # => "There once was a man from Peru\nWhose limericks stopped on line two\n"