# R Program to how to find common elements between two dataframe in r

## How to find elements that are common but only come once to both given data frames

Here we are explaining how to write an R program to find elements that are common but only come once to both given data frames. Here we are using a built-in function union(). The function union() helps to calculate the union of subsets of a probability space. The syntax of this function is,

``````
union(x,y, …)
```
```

Where x, y vectors, data frames, or ps objects containing a sequence of items. And dots(...) indicates the arguments to be passed to or from other methods.

## How to find elements that are common but only come once to both given data frames in the R program

Below are the steps used in the R program to find elements that are common but only come once to both given data frames. In this R program, we directly give the data frame to a built-in function. Here we are using variables X, Y for holding different data frames. Finally, find the common elements but only come once to both given data frames by calling the function union() like union(X, Y).

## ALGORITHM

STEP 1: Assign variables X, Y with data frames

STEP 2: First print original data frames

STEP 3:  Find the common elements but only come once to both the data frames by calling like union(X, Y)

STEP 4:  Store the result in the variable result

STEP 5: Print the final data frame

## R Source Code

```                                          ```X = c("a", "b", "c", "d", "e")
Y = c("d", "e", "f", "g")
print("Original Dataframes")
print(X)
print(Y)
print("Elements that are common but only come once to both given data frames:")
result = union(X, Y)
print(result)
```
```

## OUTPUT

```[1] "Original Dataframes"
[1] "a" "b" "c" "d" "e"
[1] "d" "e" "f" "g"
[1] "Elements that are common but only come once to both given data frames:"
[1] "a" "b" "c" "d" "e" "f" "g"```
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