subset of variables that have pattern in r

To subset variables that have a pattern in R, you can use the grep() function to find the indices of the variables that match the pattern and then use these indices for subsetting.

Here's an example:

main.r
# Create a sample data frame
df <- data.frame(id = 1:5,
                 variable_a = c(1,2,3,4,5),
                 variable_b = c(6,7,8,9,10),
                 variable_c = c(11,12,13,14,15),
                 variable_d = c(16,17,18,19,20))

# Find the indices of variables that contain the pattern "variable"
variable_indices <- grep("variable", colnames(df))

# Subset the data frame by the identified variable indices
df_subset <- df[, variable_indices]

# View the resulting subset of variables
df_subset
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In this example, we first create a sample data frame df with 4 variables with names that contain the string "variable". We then use grep() to find the indices of the variables that contain the pattern "variable". We save these indices in the variable_indices variable. Finally, we subset the data frame df using the identified variable indices to create a new data frame df_subset that only contains the variables that match the pattern.