R语言|subset()函数用法
### subset 函数 airquality <- airquality #选取Temp大于80的行,保留Ozone,temp两列 subset(airquality, Temp > 80, select = c(Ozone, Temp)) #选取day等于1的行,删去temp列 subset(airquality, Day == 1, select = -Temp) #选取ozone到wind列 subset(airquality, select = Ozone:Wind)