Golang Program To Find Common Array Elements

In this tutorial, we will see to write a go language program to find common elements in two arrays.

Find Common Array Elements Using User-Defined Function

The following code illustrates how we can find the common elements in two different arrays of strings.

Algorithm

Step 1 − import the fmt package.

Step 2 − Define a function named intersection() that accepts the two arrays as arguments and returns the resultant array as an output to the function.

Step 3 − Create an empty array of strings called out and a map called bucket.

Step 4 − Use for loop to iterate over the two arrays and check if the current element of one array is equal to the elements of the other.

Step 5 − If the condition is true then we need to store that element in the empty array created above and flip the Boolean value of the bucket map.

Step 6 − Repeat the above process until whole arrays are checked and return the final value.

Step 7 − Start the main() function.

Step 8 − Initialize two arrays of strings and store values to them and print these two arrays on the screen.

Step 9 − Call the intersection() function by passing the two arrays as arguments to the function and store the final result in a different variable.

Step 10 − This variable contains the array that has the common elements.

Step 11 − Print the result on the screen using fmt.Println() function.

Example

package main
import "fmt"
func intersection(arr1, arr2 []string) []string {
   out := []string{}
   bucket := map[string]bool{}
   for _, i := range arr1 {
      for _, j := range arr2 {
         if i == j && !bucket[i] {
            out = append(out, i)
            bucket[i] = true
         }
      }
   }
   return out
}
func main() {
   arr1 := []string{"one", "two", "three", "four"}
   fmt.Println("The first array entered is:", arr1)
   arr2 := []string{"two", "four"}
   fmt.Println("The second array entered is:", arr2)
   result := intersection(arr1, arr2)
   fmt.Println("The common elements of the above two arrays are:", result)
}

Output

The first array entered is: [one two three four]
The second array entered is: [two four]
The common elements of the above two arrays are: [two four]

Find Common Array Elements In An Array Of Integers Using External Functions

In this example, we will write a go language program to find common integer array elements using user-defined functions.

Algorithm

Step 1 − import the fmt package.

Step 2 − Define a function named intersection() that accepts the two arrays as arguments and returns the resultant array as output to the function.

Step 3 − Create an a map called m with keys as integers and value as Booleans.

Step 4 − Use for loop to iterate over the array and store its value to the map.

Step 5 − Now, use another for loop to iterate over the second array if the current element of array is equal to the map then store this element in a new array.

Step 6 − Repeat the above process until whole arrays are checked and return the final array.

Step 7 − Start the main() function.

Step 8 − Initialize two arrays of integers and store values to them print these two arrays on the screen.

Step 9 − Call the intersection() function by passing the two arrays as arguments to the function and store the final result obtained in a different variable.

Step 10 − This variable contains the array that has the common elements.

Step 11 − Print the result on the screen using fmt.Println() function.

Example

package main
import (
   "fmt"
)

// creating an Intersection function
func intersection(a, b []int) (c []int) {
   m := make(map[int]bool)
   for _, item := range a {
   
      // storing value to the map
      m[item] = true
   }
   for _, item := range b {
      if _, ok := m[item]; ok {
         c = append(c, item)
      }
   }
   return c
}
func main() {
   arr1 := []int{1, 2, 3, 4, 5}
   fmt.Println("The first array entered is:", arr1)
   arr2 := []int{4, 5, 6, 7}
   fmt.Println("The second array entered is:", arr2)
   result := intersection(arr1, arr2)
   fmt.Println("The common elements of the above two arrays are:", result)
}

Output

The first array entered is: [1 2 3 4 5]
The second array entered is: [4 5 6 7]
The common elements of the above two arrays are: [4 5]

Conclusion

We have successfully compiled and executed a go language program to find the common elements of two arrays along with the examples.