R Programming: Create Inner, Outer, Left, and Right Joins

R Programming: Data frame Exercise-13 with Solution

Write a R program to create inner, outer, left, right join(merge) from given two data frames.

Sample Solution :

R Programming Code :

# Create the first data frame with a column 'numid'
df1 = data.frame(numid = c(12, 14, 10, 11))

# Create the second data frame with a column 'numid'
df2 = data.frame(numid = c(13, 15, 11, 12))

# Print a message indicating the start of the Left Outer Join
print("Left outer Join:")

# Perform a Left Outer Join on 'numid' between df1 and df2
# This includes all rows from df1 and matched rows from df2
result = merge(df1, df2, by = "numid", all.x = TRUE)

# Print the result of the Left Outer Join
print(result)

# Print a message indicating the start of the Right Outer Join
print("Right outer Join:")

# Perform a Right Outer Join on 'numid' between df1 and df2
# This includes all rows from df2 and matched rows from df1
result = merge(df1, df2, by = "numid", all.y = TRUE)

# Print the result of the Right Outer Join
print(result)

# Print a message indicating the start of the Outer Join
print("Outer Join:")

# Perform a Full Outer Join on 'numid' between df1 and df2
# This includes all rows from both df1 and df2
result = merge(df1, df2, by = "numid", all = TRUE)

# Print the result of the Outer Join
print(result)

# Print a message indicating the start of the Cross Join
print("Cross Join:")

# Perform a Cross Join (Cartesian Product) between df1 and df2
# This includes all combinations of rows from both df1 and df2
result = merge(df1, df2, by = NULL)

# Print the result of the Cross Join
print(result)

Visual Presentation :

Output:

[1] "Left outer Join:"
  numid
1    10
2    11
3    12
4    14
[1] "Right outer Join:"
  numid
1    11
2    12
3    13
4    15
[1] "Outer Join:"
  numid
1    10
2    11
3    12
4    13
5    14
6    15
[1] "Cross Join:"
   numid.x numid.y
1       12      13
2       14      13
3       10      13
4       11      13
5       12      15
6       14      15
7       10      15
8       11      15
9       12      11
10      14      11
11      10      11
12      11      11
13      12      12
14      14      12
15      10      12
16      11      12      

Explanation:

• Create Data Frames:
• df1 = data.frame(numid = c(12, 14, 10, 11))
• Creates the first data frame df1 with a column numid containing the values 12, 14, 10, and 11.
• df2 = data.frame(numid = c(13, 15, 11, 12))
• Creates the second data frame df2 with a column numid containing the values 13, 15, 11, and 12.
• Left Outer Join:
• print("Left outer Join:")
• Prints a message indicating that the following output will be from a Left Outer Join.
• result = merge(df1, df2, by = "numid", all.x = TRUE)
• Performs a Left Outer Join between df1 and df2 on the numid column, including all rows from df1 and matching rows from df2.
• print(result)
• Prints the result of the Left Outer Join.
• Right Outer Join:
• print("Right outer Join:")
• Prints a message indicating that the following output will be from a Right Outer Join.
• result = merge(df1, df2, by = "numid", all.y = TRUE)
• Performs a Right Outer Join between df1 and df2 on the numid column, including all rows from df2 and matching rows from df1.
• print(result)
• Prints the result of the Right Outer Join.
• Outer Join:
• print("Outer Join:")
• Prints a message indicating that the following output will be from a Full Outer Join.
• result = merge(df1, df2, by = "numid", all = TRUE)
• Performs a Full Outer Join between df1 and df2 on the numid column, including all rows from both df1 and df2.
• print(result)
• Prints the result of the Full Outer Join.
• Cross Join:
• print("Cross Join:")
• Prints a message indicating that the following output will be from a Cross Join (Cartesian Product).
• result = merge(df1, df2, by = NULL)
• Performs a Cross Join (Cartesian Product) between df1 and df2, which includes all combinations of rows from both data frames.
• print(result)
• Prints the result of the Cross Join.

R Programming Code Editor:

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