试试mean(..., na.rm = TRUE)

烦请把代码再贴一下

setwd("C:\\Users\\lenovo\\Desktop\\R语言")
Temperature<-read.table(file="Temperature.txt",header=TRUE)
str(Temperature)
Tem.Year<-Temperature[Temperature$Year>=1990&Temperature$Year<=2005,]
d<-matrix(NA,16,12)
for(i in 1990:2005){
Tem.i<-Tem.Year[Tem.Year$Year==i,]
for(j in 1:12){
Month.j<-Tem.i[Tem.i$Month==j,]
d[i,j]<-mean(Month.j$Temperature,header=TRUE)
d[i,j]
}
}
d

在论坛贴代码真麻烦