Golang Program to Check if An Array Contains a Given Value

In this tutorial we will learn how to check if a given value is present in a Go−lang array or not. We will use 2 methods for this.

Method 1: Using a for loop directly in the main function

We will use a for loop to iterate over the elements of an array in Golang and check for the equality of values using the equality operator. If the values match then we can stop the iteration and say that the given value is present in the array.

Method 2: Using the function

Golang does not have any pre-defined library function method for this, so we need to create our own function.

Example 1: Golang Program to check if an Array Contains a Specific.

Syntax

var array_name [length] Type

In Golang to initialize an array, we need to specify three things. The first one is the name of the array followed by its size and then the data type of the value we wish to store in it.

For example, var number[10] int – this will initialize an array named number of integer data type and will a lot 10 memory at contiguous memory locations to store value in it.

Algorithm

• Step 1 − Import the package fmt.

• Step 2 − Start the function main().

• Step 3 − Declare and Initialize an array, a variable of data type int and a boolean variable.

• Step 4 − Iterate over the array using for loop.

• Step 5 − Print the result on the screen using fmt.Printf().

Example

// GOLANG PROGRAM TO CHECK IF AN ARRAY CONTAINS A GIVEN VALUE
package main
import "fmt"

// fmt package provides the function to print anything
func main() {

   // initialize an array and store value in it
   array := [5]int {1, 2, 3, 4, 5}
   
   // initialize a variable of data type int
   var element int = 4
   fmt.Println("The element to check = ",element)
   
   // initialize a datatype of Boolean and define it to false
   var result bool = false
   
   // iterate over the array using for loop and break if values match
   for i := 0;
   i < len(array);
   i++ {
      // checking if the array contains the given value
      if array[i] == element {
      // changing the boolean variable
            result = true
            break
         }
      }
      
      // printing the final result
      if result {
         fmt.Println("Array", array, "Contains the given Value", element)
      } else {
         fmt.Println("Array", array, "does not Contains the given Value", element)
      }
   }

Output

The element to check = 4 
Array [1 2 3 4 5] Contains the given Value 4

Description of the Code

1. First, we import the package fmt that allows us to print anything.

2. Then we start the main() function.

3. Initialize an array of data type int and assign value to it.

4. Also initialize a variable to store the integer value that we wish to check.

5. Initialize a Boolean variable and initially store false in it.

6. Iterate over the array and use if condition to check wheather it contains the above initialized variable or not.

7. If it contains the variable flip the Boolean variable and break the loop.

8. Print the result on the screen.

Example 2: Golang Program to Check if an Array contains a Specific Element using Function

Syntax

func function_name([parameters]) [return_types]{
   Body of the function
}

Algorithm

• Step 1 − Import the package fmt

• Step 2 − Create the function isAvailable().

• Step 3 − Start the function main().

• Step 4 − Initialize the array of string

• Step 5 − Call the function isAvailable().

• Step 6 − Print the result on the screen using fmt.Printf().

Example

package main
import "fmt"

// defining the function with a parameter of string
// type and have a return type bool
func isAvailable(alpha []string, str string) bool {

   // iterate using the for loop
   for i := 0;
   i < len(alpha);
   i++ {
      // check      
      if alpha[i] == str {
         // return true
         return true
      }
   }
   return false
}
// Start the function main()
func main() {
   // Declare and initialize string datatype
   alpha := []string {"Akshay", "Emma", "David", "Akhil"}
   fmt.Println("Given List = ",alpha)
   
   // initializing a variable of data type string
   var toCheck string = "Akhil"
   fmt.Println("Value to search = ",toCheck)
   
   // calling the isAvailable() function
   result := isAvailable(alpha, toCheck)
   if result {
      fmt.Println(toCheck, "is present in the array of strings", alpha)
   }
}

Output

Given List = [Akshay Emma David Akhil] 
Value to search = Akhil 
Akhil is present in the array of strings [Akshay Emma David Akhil]

Description of the Code

1. First, we have to import the fmt package that allows us to print anything on the screen.

2. Then we have to create a function that will take care of our logic.

3. We have created isAvailable() function that takes two arguments as strings one is the array of strings and another is the string that we wish to check. The function returns a Boolean value i.e either true or false.

4. In this loop we have used for loop to iterate over the array.

5. Then we have used the if conditionals to check whether the available string is present in the array or not.

6. If it is present then true and is returned. Otherwise this function will return false.

7. Start the main() function.

8. Initialize an array of strings and assign value to it.

9. Initialize a toCheck variable of data type string that will contain the value to be checked.

10. Call the isAvailable() function and pass the array of string and the toCheck variable as arguments to it.

11. Store the value returned by the function in a separate variable.

12. Print the result on the screen.

Conclusion

We have successfully compiled and executed the Golang program code to check if the element is present in the array. We have used 2 different methods to show this. First is direct method in which we have used a for loop to iterate over the array.

In the second method we have created a function and call it from the main function to check the same.