How to Iterate Over a Vector in Reverse Order in R - Step by Step Examples

How to Iterate Over a Vector in Reverse Order in R ?

Answer

To iterate over a vector in reverse order in R, you can use the rev function to reverse the vector first, then iterate over it using a for loop or one of the apply functions.

✐ Examples

1 Iterate Over a Numeric Vector in Reverse Order

In this example,

We create a numeric vector named num_vec with several numeric values.
We use the rev function to reverse the order of elements in num_vec.
We then iterate over the reversed vector using a for loop, starting from the first element (which was the last element before reversal) to the last element.
Inside the loop, we print each element of the vector, which effectively traverses the vector in reverse order.

R Program

num_vec <- c(10, 20, 30, 40, 50)
reversed_num_vec <- rev(num_vec)
for (num in reversed_num_vec) {
    print(num)
}

Output

[1] 50
[1] 40
[1] 30
[1] 20
[1] 10

2 Iterate Over a Character Vector in Reverse Order

In this example,

We create a character vector named char_vec with several string values.
We use the rev function to reverse the order of elements in char_vec.
We then iterate over the reversed vector using the sapply function, which applies a function to each element of the vector.
Inside the sapply function, we define an anonymous function that prints each element of the vector. This effectively traverses the vector in reverse order.

R Program

char_vec <- c("apple", "banana", "cherry", "date")
reversed_char_vec <- rev(char_vec)
sapply(reversed_char_vec, function(x) print(x))

Output

[1] "date"
[1] "cherry"
[1] "banana"
[1] "apple"

Summary

In this tutorial, we learned How to Iterate Over a Vector in Reverse Order in R language with well detailed examples.

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How to Iterate Over a Vector in Reverse Order in R - Step by Step Examples

How to Iterate Over a Vector in Reverse Order in R ?

Answer

✐ Examples

1 Iterate Over a Numeric Vector in Reverse Order

R Program

Output

2 Iterate Over a Character Vector in Reverse Order

R Program

Output

Summary

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