整群抽样中的问题：'mixed with negative subscripts'
Problem in cluster sampling: 'mixed with negative subscripts'
我正在尝试进行整群抽样，但遇到了这个错误：
Error in xj[i] : only 0's may be mixed with negative subscripts
原因是什么以及如何解决？感谢您的帮助！
代码如下：
#simulate some data
y <- rnorm(20)
x <- rnorm(20)
z <- rep(1:5, 4)
w <- rep(1:4, each=5)
dd <- data.frame(id=z, cluster=w, x=x, y=y)
clusters <- split(dd, dd$cluster) #split into clusters
k <- length(clusters) #length of clusters
# This function generates a cluster sample
clsamp <- function() dd[unlist(clusters[sample.int(k, k, replace = TRUE)], use.names = TRUE), ]
clsamp()
我收到这个错误：Error in xj[i] : only 0's may be mixed with negative subscripts
找到答案：将分割线改为clusters <- split(seq_len(nrow(dd)), dd$cluster)
我正在尝试进行整群抽样，但遇到了这个错误：
Error in xj[i] : only 0's may be mixed with negative subscripts
原因是什么以及如何解决？感谢您的帮助！
代码如下：
#simulate some data
y <- rnorm(20)
x <- rnorm(20)
z <- rep(1:5, 4)
w <- rep(1:4, each=5)
dd <- data.frame(id=z, cluster=w, x=x, y=y)
clusters <- split(dd, dd$cluster) #split into clusters
k <- length(clusters) #length of clusters
# This function generates a cluster sample
clsamp <- function() dd[unlist(clusters[sample.int(k, k, replace = TRUE)], use.names = TRUE), ]
clsamp()
我收到这个错误：Error in xj[i] : only 0's may be mixed with negative subscripts
找到答案：将分割线改为clusters <- split(seq_len(nrow(dd)), dd$cluster)