I have two data frames
df1 <- data.frame(Region = c(1:5), Code = c(10,11,12,15,15), date = c("2018-12","2018-11","2019-01","2019-01","2019-02"))
df2 <- data.frame(Code = c(10,11,12,13,14,15,16,17,18,19),"2018-10" = c(50:59),"2018-11" = c(20:29),"2018-12" = c(25:34),"2019-01" = c(32:41),"2019-01" = c(40:49),"2019-02" = c(40:49))
I would like to match and store the corresponding values of df1$Region in df3.
The result should look as follows
df3 <- data.frame(Region = c(1:5),Results=c(25,21,34,45,45))
We can use row/column
indexing to extract the values by match
ing the the 'Code' columns as row index, and the 'date/column names` of the the two dataset to get the column index (without using any external packages)
cbind(df1['Region'], Results = df2[-1][cbind(match(df1$Code, df2$Code),
match(df1$date,
sub('^X(\\d{4})\\.', "\\1-", names(df2)[-1])))])
# Region Results
#1 1 25
#2 2 21
#3 3 34
#4 4 37
#5 5 45
NOTE: The column names in the OP's post had ^X
at the beginning and its format was .
instead of -
as it is created with check.names = TRUE
(default)
if the datasets were created with check.names = FALSE
, the above solution can be further simplified
cbind(df1['Region'], Results = df2[-1][cbind(match(df1$Code, df2$Code),
match(df1$date, names(df2)[-1]))])
# Region Results
#1 1 25
#2 2 21
#3 3 34
#4 4 37
#5 5 45
If the column names are duplicated and wants to match based on that info, then
i1 <- duplicated(df1$date)
v1 <- numeric(nrow(df1))
v1[!i1] <- df2[-1][cbind(match(df1$Code[!i1],
df2$Code),match(df1$date[!i1], names(df2)[-1]))]
v1[i1] <- rev(df2[-1])[cbind(match(df1$Code[i1],
df2$Code),match(df1$date[i1], rev(names(df2)[-1])))]
cbind(df1['Region'], Results = v1)
# Region Results
#1 1 25
#2 2 21
#3 3 34
#4 4 45
#5 5 45
NOTE: No external packages used
One option involving dplyr
and tidyr
could be:
df1 %>%
inner_join(df2 %>%
pivot_longer(-Code), by = c("Code" = "Code",
"date" = "name"))
Region Code date value
1 1 10 2018-12 25
2 2 11 2018-11 21
3 3 12 2019-01 34
4 4 15 2019-01 37
5 5 15 2019-02 45
I considered two columns in df2 with the same name as a typo.
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