CODEWITHSUNDEEP
r
salhin
salhin

Reputation: 2654

Reverse row order in a data frame

Suppose I got the following data frame:

A   B
1   2
3   4
5   6

And I want to reverse row order in all columns (turn it "upside down"):

A   B
5   6
3   4
1   2

I used the following code

sort(df[ , 1:2], decreasing = TRUE)

However, it gives me the following error:

Error in `[.data.frame`(x, order(x, na.last = na.last, decreasing = decreasing)) : undefined columns selected

when I specify only one column it works but I need both the columns to be sorted at once.

Upvotes: 3

Views: 6004

Answers (1)

Rich Scriven
Rich Scriven

Reputation: 99331

You could use rev to reverse the row names

df[rev(rownames(df)),]
#   A B
# 3 5 6
# 2 3 4
# 1 1 2

If you want to correct the new reversed row names, you could write a little function

flip <- function(data) {
    new <- data[rev(rownames(data)), ]
    rownames(new) <- NULL
    new
}
flip(df)
#   A B
# 1 5 6
# 2 3 4
# 3 1 2

Upvotes: 7

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