transform a dataframe of many columns of strings to a new dataframe of two columns that contains column pairs from left to right in r in r in r

main.r
# Create a sample dataframe
df <- data.frame(
  col1 = c("A", "B", "C"),
  col2 = c("D", "E", "F"),
  col3 = c("G", "H", "I"),
  col4 = c("J", "K", "L")
)

# Define a function to transform the dataframe
transform_df <- function(df) {
  # Initialize an empty dataframe to store the result
  result <- data.frame(col1 = character(), col2 = character())
  
  # Loop through the columns of the dataframe in steps of 2
  for (i in 1:(ncol(df) - 1)) {
    # Select the current column pair
    col_pair <- df[, c(i, i + 1)]
    
    # Convert the column pair to a dataframe with two columns
    col_pair_df <- data.frame(col1 = col_pair[, 1], col2 = col_pair[, 2])
    
    # Bind the column pair dataframe to the result dataframe
    result <- rbind(result, col_pair_df)
  }
  
  # Return the result dataframe
  return(result)
}

# Apply the transformation function to the dataframe
new_df <- transform_df(df)

# Print the result dataframe
print(new_df)
948 chars
35 lines

main.r
  col1 col2
1    A    D
2    B    E
3    C    F
4    D    G
5    E    H
6    F    I
7    G    J
8    H    K
9    I    L
120 chars
11 lines