One error you may encounter in R is:

Error in sum(x) : invalid 'type' (character) of argument

This error occurs when you attempt to perform some mathematical operation (like taking the sum, mean, count, etc.) on a character vector.

This tutorial shares how to resolve this error in practice.

**How to Reproduce the Error**

Suppose we create the following data frame in R:

**#create data frame
df <- data.frame(team=c('A', 'A', 'A', 'B', 'B', 'B'),
points=c(10, 12, 15, 20, 26, 25),
rebounds=c(7, 8, 8, 14, 10, 12))
#view data frame
df
team points rebounds
1 A 10 7
2 A 12 8
3 A 15 8
4 B 20 14
5 B 26 10
6 B 25 12**

Now suppose we attempt to calculate the sum of the ‘team’ column:

**#attempt to calculate sum of values in 'team' column
sum(df$team)
Error in sum(df$team) : invalid 'type' (character) of argument
**

We receive an error because the ‘team’ column is a character column.

We can confirm this by using the** class()** function:

**#view class of 'team' column
class(df$team)
[1] "character"
**

**How to Fix the Error**

The way to get around this error is to only use mathematical operations with numeric vectors.

For example, we could use the **sum()** function to calculate the sum of the values in the ‘points’ column:

**#calculate sum of values in 'points' column
sum(df$points)
[1] 108
**

We could also calculate the sum of the points values, grouped by team:

**#calculate sum of points, grouped by team
aggregate(points ~ team, df, sum)
team points
1 A 37
2 B 71
**

We could even calculate the sum of the points *and* rebounds values, grouped by team:

**#calculate sum of points and sum of rebounds, grouped by team
aggregate(. ~ team, df, sum)
team points rebounds
1 A 37 23
2 B 71 36
**

Notice that we don’t receive an error with any of these operations because we’re only attempting to calculate the sum for numeric variables.

**Additional Resources**

The following tutorials explain how to fix other common errors in R:

How to Fix: the condition has length > 1 and only the first element will be used

How to Fix: non-numeric argument to binary operator

How to Fix: dim(X) must have a positive length

How to Fix: error in select unused arguments