第一种问题
>mydatas<- function(x,na.omit=F){
if (na.omit)
x<- x[!is.na(x)]
m<- mean(x)
n<- length(x)
s<- sd(x)
skew<-sum((x-m)^3/s^3)/n
kurt<- sum((x-m)^4/s^4)/n -3
return(c(n=n,mean=m,stdev=s,skew=skew,kurtosi=kurt))}
dstats<-function(x)sapply(x,mystats)
mydata<- c("PM251","OC1","BC1","SO41","NH41","NIT1","SOIL1","NO21","ft41","tsh1","TSH0","tpo1","tpo1g")
by(data01[mydata],data01$ID,dstats) 返回值出现Error in +if (na.omit) { : 一进列运算符的参数不对
第二种问题
>mydatas<- function(x,na.omit=F){
if (na.omit)
x<- x[!is.na(x)]
m<- mean(x)
n<- length(x)
s<- sd(x)
return(c(n=n,mean=m,stdev=s,))}
>dstats<-function(x)apply(x,mystats)
>mydata<- c("PM251","OC1","BC1","SO41","NH41","NIT1","SOIL1","NO21","ft41","tsh1","TSH0","tpo1","tpo1g")
>by(data01[mydata],data01$ID,dstats)
返回值出现Error in match.fun(FUN) : 缺少参数"FUN",也没有缺省值
Called from: match.fun(FUN)