如何在R中的向量中返回最大值

Question

stock.prices=c(21,25,23,22,32)

week.days=c("mon","tues","wed",thu","fri")

names(stock.prices)=week.days

1. 查找大于24的股票价格

2. 查找本周的最高股价

第二个代码为什么不起作用

stock.prices[stock.prices>24]

stock.prices[max(stock.prices)]