1

我试图在循环中按名称删除变量时卡住了,发现不可能(?)用 Magrittr 管道做到这一点:

eg.names <- unlist(lapply(0:4, function(x){
  eg <- paste0('example.var.',as.character(x))
}))

for (examplename in eg.names) {
  assign(examplename, 10)
}

library('magrittr')

for (examplename in eg.names) {
  examplename %>%
    rm(list = as.character(.))
  print(exists(examplename))
}

### Gives:

# [1] TRUE
# [1] TRUE
# [1] TRUE
# [1] TRUE
# [1] TRUE
# Warning messages:
#   1: In rm(list = .) : object 'example.var.0' not found
# 2: In rm(list = .) : object 'example.var.1' not found
# 3: In rm(list = .) : object 'example.var.2' not found
# 4: In rm(list = .) : object 'example.var.3' not found
# 5: In rm(list = .) : object 'example.var.4' not found

### Piping `examplename` to `rm(list = as.character(.))` also doesn't work...

### Working non-%>% version:

for (examplename in eg.names) {
  rm(list = as.character(examplename))
}

有什么我应该避免在 Magrittr 做的事情,或者实际上有什么方法可以解决吗?

4

1 回答 1

1

这工作得很好:

for (examplename in eg.names) {
  examplename %>%
    rm(list = .,envir=globalenv())
  print(exists(examplename))
}
# [1] FALSE
# [1] FALSE
# [1] FALSE
# [1] FALSE
# [1] FALSE
于 2017-06-09T17:47:21.053 回答