Error in usemethod(“group_by”) : no applicable method for ‘group_by’ applied to an object of class “c(‘double’, ‘numeric’)”

This error message indicates that there is an issue with the usemethod(“group_by”) function because it cannot be applied to an object of class “c(‘double’, ‘numeric’)”.

To understand this error, let’s break it down:

• The error message states that the function “group_by” cannot be applied to an object of class “c(‘double’, ‘numeric’)”. In R, class refers to the data type of an object. In this case, the object has a class of “double” and “numeric”, which typically represent numbers.
• The “group_by” function is commonly used in R packages like dplyr to group data based on certain variables. It is typically applied to data frames or similar data structures.
• Therefore, the error message suggests that you are trying to use the “group_by” function on a numeric object, which is not supported.

To resolve this error, ensure that you are applying the “group_by” function to a suitable data structure such as a data frame. Here’s an example to illustrate the correct usage:

<pre><code class="language-r"># Load the dplyr package
library(dplyr)

# Create a data frame
df <- data.frame(Name = c("John", "Alice", "Mike", "Sarah"),
                 Age = c(25, 30, 28, 32),
                 City = c("New York", "Paris", "London", "Tokyo"))

# Group the data frame by the 'City' variable
grouped_df <- df %>% group_by(City)

# Perform some summary operation, such as calculating the mean age by city
summary_df <- grouped_df %>% summarize(Mean_Age = mean(Age))

# View the resulting summary data frame
summary_df
</code></pre>

In the above example, we create a data frame 'df' with three variables: 'Name', 'Age', and 'City'. We then use the 'group_by' function from the dplyr package to group the data frame by the 'City' variable. Finally, we calculate the mean age for each city using the 'summarize' function.

By ensuring that you apply the 'group_by' function to a suitable data structure, such as a data frame, you should be able to avoid this particular error.