R:根据在一列中检测到的字符串从另一列中提取数据

Question

我有一个很大的数据集要总结。这些数据是健康记录，每个人都检查过许多器官/组织，诊断是以叙述的形式输入的。我有几个关键的诊断术语想要找到，然后我想知道哪些器官与诊断有关。

示例(所有条目转换为字符串)

dataframe1

Organ          Diagnosis
lungs          interstitial pneumonia
liver          hepatic congestion ; diffuse
cerebrum       traumatic disruption and hemorrhage       
adrenal gland  focal hemorrhage

dataframe2

Keywords
congestion
hemorrhage
trauma
pneumonia

我想在dataframe1$Diagnosis中搜索与dataframe2$Keywords匹配的字符串，对于每个匹配项，返回在dataframe1$Organ的相应行中输入的器官。

数据结构

dataframe1 <- structure(list(Organ = c("lungs", "liver", "cerebrum", "adrenal gland"
), Diagnosis = c("interstitial pneumonia", "hepatic congestion ; diffuse", 
"traumatic disruption and hemorrhage", "focal hemorrhage")), .Names = c("Organ", 
"Diagnosis"), class = "data.frame", row.names = c(NA, -4L))

dataframe2 <- data.frame(Keywords=c("congestion","hemorrhage","trauma","pneumonia"),stringsAsFactors=FALSE)

Answer 1

我们可以使用grep

sapply(dataframe2$Keywords, function(x) 
       toString(trimws(dataframe1[,1][grep(x, dataframe1[,2])])))

Answer 2

我认为返回匹配内容的堆叠列表可能很有价值，例如：

stack(
  sapply(dataframe2$Keywords, 
         function(x) dataframe1$Organ[grepl(x, dataframe1$Diagnosis)])
)

#         values        ind
#1         liver congestion
#2      cerebrum hemorrhage
#3 adrenal gland hemorrhage
#4      cerebrum     trauma
#5         lungs  pneumonia