R语言，函数报错解决

Question

#APdobs_NTPD.fn函数：计算NTPD观察值,长度为focalsp的长度

focalsp<-read.csv("1.csv",header=T,fileEncoding="GBK")  ##目标个体的种名
pdmatrix<-read.csv("2.csv",header=T,fileEncoding="GBK")#系统发育距离矩阵
sample<-read.csv("1.csv",header=T,fileEncoding="GBK")#周围邻体的其他种类
as.matrix(focalsp)
as.matrix(pdmatrix)
as.matrix(sample)
APdobs_NTPD.fn =function(focalsp,pdmatrix,sample)
  #focalsp为目标个体的种名，pdmatrix为系统发育距离矩阵(标准化成0-1,参考Liza的课件)，spinsample为周围邻体的其他种类
{
  pdtofocal.min =numeric()
  for(i in 1:length(focalsp))
  {
    spinsample=rownames(sample)[sample[,i]!=0]
    spinsample.abund=sample[,i][sample[,i]!=0]
    focalsp.pos=which(rownames(pdmatrix)==focalsp[i])
    spinsample.pos=match(spinsample,colnames(pdmatrix))
    pdtofocal=numeric()
    for(j in 1:length(spinsample.pos))
    {
      pdtofocal[j]=pdmatrix[focalsp.pos,spinsample.pos[j]]
    }
    pdtofocal.min[i]=min(pdtofocal)
  }
  return(pdtofocal.min)
}

write.table(APdobs_NTPD.fn,"APdobs_NTPD.fn")

报错：Error in as.data.frame.default(x[[i]], optional = TRUE) :
cannot coerce class ‘"function"’ to a data.frame

Answer 1

results <- APdobs_NTPD.fn(focalsp,pdmatrix,sample)
write.table(results, "APdobs_NTPD.fn")