如何遍历列表列表

Question

我想迭代一次列表列表(在数据中)，以便为每个活检站点添加一个随机数，除了if活检站点:没有，在这种情况下，不会发生粘贴。

输入：

list(c("Biopsy site: Duodenal bulb", "Biopsy site: Stomach", 
"Biopsy site: None", "Biopsy site: D2 - 2nd part of duodenum"
), "Biopsy site: None", c("Biopsy site: D2 - 2nd part of duodenum", 
"Biopsy site: Stomach", "Biopsy site: Oesophagus"), c("Biopsy site: Stomach", 
"Biopsy site: None", "Biopsy site: Oesophagus"), c("Biopsy site: Duodenal bulb", 
"Biopsy site: Stomach"))

预期输出

[1] "3 Biopsy site: Duodenal bulb"             "5 Biopsy site: Stomach"                   "Biopsy site: None"                      "7 Biopsy site: D2 - 2nd part of duodenum"

[[2]]
[1] "Biopsy site: None"

[[3]]
[1] "8 Biopsy site: D2 - 2nd part of duodenum" "3 Biopsy site: Stomach"                   "7 Biopsy site: Oesophagus"               

[[4]]
[1] "6 Biopsy site: Stomach"    "Biopsy site: None"       "3 Biopsy site: Oesophagus"

[[5]]
[1] "2 Biopsy site: Duodenal bulb" "3 Biopsy site: Stomach"      

尝试

    lapply(OGDProcedureDf$BiopsyType, function(p)
ifelse(!grepl("None",OGDProcedureDf$BiopsyType),paste(sample(1:10),OGDProcedureDf$BiopsyType),"")
        )

但我认为问题是，这是一个嵌套列表，所以我需要嵌套的lapply？

Answer 1

没有嵌套的lapply是必要的，而且您的尝试实际上非常接近：

lst_0 <- list(c("Biopsy site: Duodenal bulb", "Biopsy site: Stomach", 
"Biopsy site: None", "Biopsy site: D2 - 2nd part of duodenum"
), "Biopsy site: None", c("Biopsy site: D2 - 2nd part of duodenum", 
"Biopsy site: Stomach", "Biopsy site: Oesophagus"), c("Biopsy site: Stomach", 
"Biopsy site: None", "Biopsy site: Oesophagus"), c("Biopsy site: Duodenal bulb", 
"Biopsy site: Stomach"))

lapply(lst_0, function(p)
  ifelse(!grepl("None",p),paste(sample(1:10),p),p)
)