Merge Two Data Frames by common Columns in R Programming – merge() Function

merge() function in R Language is used to merge two data frames by common columns.

Syntax: merge(arg1, arg2, by.x, by.y)

Parameters:
arg1 and arg2: Data frames to be merged
by.x: Common argument of first data frame
by.y: Common argument of second data frame

Example 1:

# R program to merge two data frames

# Creating data frames
df1 <- data.frame(row1 = c("a", "b", "c"), row2 = c("d", "e", "f"))
df2 <- data.frame(col1 = c("a", "b", "c"), col2 = c("Hello", "Geeks", "gfg"))

# Calling merge() function
df <- merge(df1, df2, by.x ="row1", by.y ="col1")
print(df)

Output:

  row1 row2  col2
1    a    d Hello
2    b    e Geeks
3    c    f   gfg

Example 2:

# R program to merge two data frames

# Creating data frames
df1 <- data.frame(row1 = c("d", "e", "f"), row2 = c(1, 2, 3))
df2 <- data.frame(col1 = c(1, 2, 3), col2 = c("Hello", "Geeks", "gfg"))

# Calling merge() function
df <- merge(df1, df2, by.x ="row2", by.y ="col1")
print(df)

Output:

  row2 row1  col2
1    1    d Hello
2    2    e Geeks
3    3    f   gfg