Best merge or join function in r -

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i have 2 dataframes df1 , df2. both have common identifier column.

df1 has unique lines each identifier. has identifier values not in df2.

df2 has multiple lines each identifier value.

i want merge 2 preserve number of rows of df2, map (repeating) relevant id rows df1 df2.

is best use merge or join or else? arguments?

thanks :)

without input data, hard provide working code. but, dplyr package's join functions super efficient kinds of joins.

in case, can try like:

library(dplyr) newdf <- left_join(df1, df2)

this keep id's in df1, while retaining duplicate rows in df2 long common column filed matches.

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