*This error occurs when you try to replace a value in a vector with a value of length zero. A value of length zero does not exist is the same as saying the value does not exist.*

*This error typically happens when trying to use the zeroth index of a vector. In R, indexes start at one, therefore the value vector[0] does not exist.*

*You can solve this error by ensuring you access values that exist in the vector, in other words, values with indexes starting from 1.*

*This tutorial will go through the error and how to solve it with code examples.*

## Table of contents

## Example: Fibonacci Sequence in R

Let’s attempt to print the first ten Fibonacci numbers in R. First we will define the function

fib <- function(n){ fib <- vector() fib[1] <- 1 fib[2] <- 1 for(i in 2:n){ fib[i] <- fib[i-1] + fib[i-2] } return(fib) }

Next, we will try to get the first ten fibonacci numbers:

fib(10)

Error in fib[i] <- fib[i - 1] + fib[i - 2] : replacement has length zero

The error occurs because we are trying to add a value to the fib vector that does not exist.

Arrays in R start with index 1, not 0. Therefore, at the first iteration of the for loop where `i = 2`

, we have:

`fib[2] <- fib[2-1] + fib[2 - 2]`

, which is:

`fib[2] <- fib[1] + fib[0]`

There is no value at `fib[0]`

, therefore R raises the error: replacement has length zero

### Solution

We can solve the error by starting the for loop at 3 instead of 2. Therefore at the first iteration of the for loop where `i = 3`

, we have:

`fib[3] <- fib[3-1] + fib[3 -2]`

, which is

`fib[3] <- fib[2] + fib[1]`

, giving

`fib[3] <- 1 + 1`

.

Let’s look at the revised function:

fib <- function(n){ fib <- vector() fib[1] <- 1 fib[2] <- 1 for(i in 3:n){ fib[i] <- fib[i-1] + fib[i-2] } return(fib) }

Let’s run the code to get the first ten Fibonacci numbers:

fib(10)

[1] 1 1 2 3 5 8 13 21 34 55

## Summary

Congratulations on reading to the end of this tutorial!

For further reading on R related errors, go to the articles:

- How to Solve R Error in sort.int(x, na.last = na.last, decreasing = decreasing, …) : ‘x’ must be atomic
- How to Solve R Error: the condition has length > 1

Go to the online courses page on R to learn more about coding in R for data science and machine learning.

Have fun and happy researching!