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Filling columns with corresponding identifiers from two data in R

I have two data frames (df1, df2). I want to fill in the AGE and SEX values ​​from df1 to df2 due to the same identifier between them. I tried several ways to use for-loop and check if the object id matches between two data frames, but I failed. The result should be the same as in df3. I have a huge data set, so I want part of the code in R to be able to do this easily. I would be grateful for your help in this. Thank.

df1:
ID    AGE   SEX
90901   39  0
90902   28  0
90903   40  1

df2:
ID     AGE  SEX  Conc
90901   NA  NA    5
90901   NA  NA    10
90901   NA  NA    15
90903   NA  NA    30
90903   NA  NA    5
90902   NA  NA    2.45
90902   NA  NA    51
90902   NA  NA    1
70905   NA  NA    0.5

result:
df3:
ID     AGE  SEX  Conc
90901   39  0     5
90901   39  0     10
90901   39  0     15
90903   40  1    30
90903   40  1    5
90902   28  1    2.45
90902   28  0    51
90902   28  0     1
70905   NA  NA    0.5
+4
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2 answers

match lapply . [[ ID , .

nm <- c("AGE", "SEX")
df2[nm] <- lapply(nm, function(x) df1[[x]][match(df2$ID, df1$ID)])
df2
#      ID AGE SEX  Conc
# 1 90901  39   0  5.00
# 2 90901  39   0 10.00
# 3 90901  39   0 15.00
# 4 90903  40   1 30.00
# 5 90903  40   1  5.00
# 6 90902  28   0  2.45
# 7 90902  28   0 51.00
# 8 90902  28   0  1.00
# 9 70905  NA  NA  0.50

, , merge.

+7

merge(df1, df2, by = "id"). . , df2 .

df2$AGE <- NULL
df2$SEX <- NULL
df3 <- merge(df1, df2, by = "id")

df2, df1, :

df2 <- subset(df2, select = -c(AGE,SEX) )
df3 <- merge(df1, df2, by = "id", all.y = TRUE)

merge ( r) , ?merge() r.

+6

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