The “semi_join” Function in R

• Package: dplyr

• Purpose: To perform a semi-join between two data frames, returning only the rows from the first data frame that have matching values in specified columns with the second data frame.

• General Class: Data Manipulation

• Required Argument(s):

• x, y: The data frames to be joined.

• by: Columns used for matching and merging.

• Notable Optional Arguments:

• suffix: A character vector of suffixes to be appended to duplicate and colliding column names.

• Example (with Explanation):

• # Load necessary packages
  library(dplyr)
  
  # Create two sample data frames
  data1 <- data.frame(
  ID = c(1, 2, 3),
  value1 = c(10, 15, 20)
  )
  
  data2 <- data.frame(
  ID = c(2, 3, 4),
  value2 = c(25, 30, 35)
  )
  
  # Perform a semi join based on the 'ID' column
  semi_joined_data <- semi_join(data1, data2, by = "ID")
  
  # Display the semi joined data
  print(semi_joined_data)

• In this example, the semi_join function from the dplyr package is used to perform a semi-join between two sample data frames (data1 and data2) based on the matching values in the ‘ID’ column. The result, semi_joined_data, contains only the rows from data1 that have matching values in data2. This function is useful when you want to identify and retain only the rows from the first data frame with matching values in the second data frame.