multivariable merge table in r

To merge two data frames in R based on multiple variables, we can use the merge() function with the by argument. The by argument should be set to a vector containing the column names that we want to merge on.

Here's an example:

main.r
# create two data frames
df1 <- data.frame(id=c(1, 2, 3, 4), time=c(1, 2, 3, 4), value=c(23, 54, 32, 87))
df2 <- data.frame(id=c(1, 2, 3, 5), time=c(1, 2, 3, 5), value=c(44, 22, 11, 99))

# merge the data frames based on 'id' and 'time'
merged_df <- merge(df1, df2, by=c("id", "time"))

# print the merged data frame
print(merged_df)
334 chars
10 lines

In this example, we have two data frames df1 and df2 with columns id, time, and value. We want to merge the data frames based on id and time, so we set the by argument in the merge() function to c("id", "time").

The resulting merged data frame merged_df will have columns for id, time, value.x, and value.y, where value.x is the value from df1 and value.y is the value from df2.

Note that if there are duplicate columns in the two data frames, the merge() function will append a .x or .y to each duplicated column to distinguish them in the merged data frame.