Error in usemethod(“mutate”): no applicable method for ‘mutate’ applied to an object of class “c(‘double’, ‘numeric’)”
This error message occurs when the “mutate” function in R is applied to an object that is not compatible with its operation, specifically when the object’s class is not supported by “mutate”.
Explanation
In R, the “mutate” function is part of the dplyr package and is used to create new variables (columns) or modify existing ones in a data frame. It is commonly used in data manipulation and data wrangling tasks.
To use the “mutate” function, you need to provide a data frame or a tibble as the first argument, followed by a series of column specifications that define the new variables or modifications to be performed. Each column specification consists of a new variable name followed by an expression that defines how to compute its values.
However, the error message you mentioned suggests that the object provided to “mutate” is of class “c(‘double’, ‘numeric’)”, which is not compatible with the expected data frame or tibble class.
Example
Let’s say we have a data frame called “df” with two columns: “x” and “y”. If we try to use “mutate” on a single column or a non-data frame object, we may encounter the mentioned error. Here’s an example:
df <- data.frame(x = c(1, 2, 3), y = c(4, 5, 6))
x_column <- df$x
# Trying to use "mutate" on a single column or non-data frame object
mutate(x_column, new_column = x + 1)
# Error in UseMethod("mutate") :
# no applicable method for 'mutate' applied to an object of class "c('double', 'numeric')"
In the above example, we assigned the "x" column of "df" to the variable "x_column". When we try to use "mutate" on "x_column" alone, without the actual data frame "df", we encounter the mentioned error as it expects a data frame or tibble.
Solution
To resolve the error, make sure you are providing a valid data frame or tibble to the "mutate" function. Check if the object you are trying to mutate is a data frame or convert it to one if needed. You can use the "as.data.frame" function to convert other objects to data frames, as shown in the example below:
# Converting a vector to a data frame with a single column
x_column_df <- as.data.frame(x_column)
# Applying mutate on the data frame
mutate(x_column_df, new_column = x + 1)
In the above example, we converted the "x_column" vector to a data frame with a single column using "as.data.frame". Then, we used "mutate" on the resulting data frame, and it successfully creates a new column called "new_column" by adding 1 to the values in "x_column".