是什么意思＆amp; - ＆gt;在红宝石

Question

试图理解这个问题的解决方案，但我不知道这个符号是什么意思＆amp; - ＆gt;可以有人帮忙

# Say you have an array for which the ith element is the price of a given
# stock on day i. Design an algorithm to find the maximum profit. You may
# complete as many transactions as you like (ie, buy one and sell one share
# of the stock multiple times). However, you may not engage in multiple
# transactions at the same time (ie, you must sell the stock before you buy
# again).


def max_profit(prices)
  prices.each_cons(2).map(&->(p1, p2){ [p2 - p1, 0].max }).reduce(0, &:+)
end

Answer 1

这是两个运营商。 ->创建一个lambda，&将其作为一个块传递。

Answer 2

涉及2名运营商：

• ->创建lambda
• &将使用Proc（或lambda）并将其作为块传递

相同的代码可以写成：

prices.each_cons(2).map { |p1, p2| [p2 - p1, 0].max }.reduce(0, &:+)