匹配列並將所有重復的元素保留在數據框列[R]中

Question

我有兩個數據框； DF1有3列，DF2有1列.DF1具有DF2中包含的所有元素，但是大多數元素都被復制，如下所示。

DF1=
***freetext***,         ***specific***,    ***ICDcode*** 

Jaundice,hepatitisA,B,C   Hepatitis A       B15
Jaundice,hepatitisA,B,C   Hepatitis B       B16
Jaundice,hepatitisA,B,C   Hepatitis C       B17.1
Jaundice,hepatitisA,B,C   Jaundice          R17
lobar Pneumonia           Lobar pneumonia   J18.1
Lobar Pneumonia ,scabies  Lobar pneumonia   J18.1
scabiess                  scabies            G10     

DF2=          
Jaundice,hepatitisA,B,C  
scabiess                            
Lobar Pneumonia ,scabies
lobar Pneumonia

我希望在兩個數據幀之間有一個匹配項，以便每當匹配發生時，都應該有一個以DF1形式出現的結果數據幀。例如， 黃疸，肝炎A，B，C應該出現4次，而不是出現一次。柱。 換句話說，應按如下所示維護副本；

Resultant data frame should appear like this.

    column1                  column2             column3
Jaundice,hepatitisA,B,C   Hepatitis A       B15
Jaundice,hepatitisA,B,C   Hepatitis B       B16
Jaundice,hepatitisA,B,C   Hepatitis C       B17.1
Jaundice,hepatitisA,B,C   Jaundice          R17

因此，我應該如何遍歷DF2在DF1（第一列）中找到一個匹配項，然后產生一個與所有其他對應行匹配的數據幀，如上所示？

這是我的腳本，但似乎無法產生我想要的結果

   newMatches<- data.frame()
for(i 1:nrow(DF1){ for(j in 1:nrow(DF2[,1]{grep(j, i, ignore.case=F, value=T)->newMatches}} 
#it doesn't produce other columns of DF1

任何幫助和建議都將不勝感激。

Answer 1

據我了解，您想過濾DF1的行，僅保留DF2中第一列存在的行。 那正確嗎？ 實現此目的的最簡單方法是

DF1[DF1[, 1] %in% DF2[, 1], ]

編輯

這是重現該示例的完整代碼：

DF1 <- structure(list(
    freetext = structure(c(1L, 1L, 1L, 1L, 2L, 3L, 4L),
        .Label = c("Jaundice,hepatitisA,B,C", "lobar Pneumonia", 
        "Lobar Pneumonia ,scabies", "scabiess"), class = "factor"),
    specific = structure(c(1L, 2L, 3L, 4L, 5L, 5L, 6L),  
        .Label = c("Hepatitis A", "Hepatitis B", "Hepatitis C", "Jaundice",
        "Lobar pneumonia", "scabies"), class = "factor"), 
    ICDcode = structure(c(1L, 2L, 3L, 6L, 5L, 5L, 4L), 
        .Label = c("B15", "B16", "B17.1", "G10", "J18.1", "R17"),
        class = "factor")),
   .Names = c("freetext", "specific", "ICDcode"),
   row.names = c(NA, -7L), class = "data.frame")

DF2 <- structure(list(
    freetext = structure(c(1L, 4L, 3L, 2L), 
        .Label = c("Jaundice,hepatitisA,B,C", 
         "lobar Pneumonia", "Lobar Pneumonia ,scabies", "scabiess"),
         class = "factor")),
    .Names = "freetext", row.names = c(NA, -4L), class = "data.frame")

result <- DF1[DF1[, 1] %in% DF2[, 1], ]

打印result給出以下輸出

                  freetext        specific ICDcode
1  Jaundice,hepatitisA,B,C     Hepatitis A     B15
2  Jaundice,hepatitisA,B,C     Hepatitis B     B16
3  Jaundice,hepatitisA,B,C     Hepatitis C   B17.1
4  Jaundice,hepatitisA,B,C        Jaundice     R17
5          lobar Pneumonia Lobar pneumonia   J18.1
6 Lobar Pneumonia ,scabies Lobar pneumonia   J18.1
7                 scabiess         scabies     G10