order a dataframe by the order of a column in another dataframe in r

To order a dataframe by the order of a column in another dataframe in R, you can use the match function to match the values in the column of the first dataframe with the values in the column of the second dataframe, and then use the resulting index to order the first dataframe.

Here is an example:

main.r
# Create the first dataframe
df1 <- data.frame(
  id = c(1, 2, 3, 4, 5),
  value = c("a", "b", "c", "d", "e")
)

# Create the second dataframe
df2 <- data.frame(
  id = c(3, 5, 1, 2, 4),
  order_value = c("x", "y", "z", "w", "v")
)

# Order df1 by the order of id in df2
df1_ordered <- df1[order(match(df1$id, df2$id)), ]

print(df1_ordered)
342 chars
17 lines

This will output:

main.r
  id value
3  3     c
5  5     e
1  1     a
2  2     b
4  4     d
66 chars
7 lines

The match function returns the index of the first occurrence of each value in df1$id in df2$id. The order function then uses these indices to order the rows of df1.

Alternatively, you can use the dplyr package and the left_join function to achieve the same result:

main.r
library(dplyr)

df1_ordered <- df1 %>%
  left_join(df2, by = "id") %>%
  arrange(match(id, df2$id)) %>%
  select(-order_value)

print(df1_ordered)
147 chars
9 lines

Note that this assumes that there are no duplicate values in the id column of df2. If there are duplicates, the match function will return the index of the first occurrence of each value, which may not be what you want. In that case, you may need to use a different approach, such as using the merge function to create a new dataframe with the combined data.