Go – For Loop Array

Go – For Loop Array

Arrays are fixed-length sequences of elements of the same type. Using a For Loop, you can efficiently process each element of an array.

In this tutorial, we will provide practical examples and explanations to demonstrate how to iterate over arrays using For loop.

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Iterating Over Arrays Using For Loop

You can use a for loop to iterate over an array either by index or using the range keyword. Below are examples of both approaches.

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Example 1: Iterating Over an Array Using Index

In this example, we will use a standard for loop to iterate over an array using its indices:

package main

import "fmt"

func main() {
    // Declare an array
    arr := [5]int{10, 20, 30, 40, 50}

    // Iterate over the array using a for loop
    for i := 0; i < len(arr); i++ {
        fmt.Printf("Index: %d, Value: %d\n", i, arr[i])
    }
}

Explanation

1. Declare an Array: The array arr of size 5 is initialized with integers.
2. Set up the For Loop: The for loop starts at index 0 and runs until it reaches the length of the array using len(arr).
3. Access Elements: Inside the loop, arr[i] accesses the value of the array at the current index i.
4. Print Elements: The index and value of each element are printed using fmt.Printf.

Output

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Example 2: Iterating Over an Array Using Range

Using the range keyword simplifies iteration by providing both the index and value of each element:

package main

import "fmt"

func main() {
    // Declare an array
    arr := [5]int{10, 20, 30, 40, 50}

    // Iterate over the array using range
    for index, value := range arr {
        fmt.Printf("Index: %d, Value: %d\n", index, value)
    }
}

Explanation

1. Declare an Array: The array arr of size 5 is initialized with integers.
2. Use Range: The range keyword is used to iterate over the array, providing both the index and value.
3. Access Elements: index stores the position, and value holds the element at that position.
4. Print Elements: The index and value are printed using fmt.Printf.

Output

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Example 3: Skipping Index or Value

In some cases, you may only need the index or the value. You can use the underscore (_) to ignore the one you don’t need:

package main

import "fmt"

func main() {
    // Declare an array
    arr := [5]int{10, 20, 30, 40, 50}

    // Only print values
    for _, value := range arr {
        fmt.Println("Value:", value)
    }

    // Only print indices
    for index := range arr {
        fmt.Println("Index:", index)
    }
}

Explanation

1. Ignore Index: Use _ in place of the index when you only need the value.
2. Ignore Value: Use _ in place of the value when you only need the index.
3. Iterate and Print: The loop iterates through the array, printing either the value or index as required.

Output

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When to Use For Loop with Arrays

You can use For Loop with Arrays:

• To access each element of the array for processing or computation.
• To find specific elements based on conditions.
• To iterate over arrays for transformations or aggregations.

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Conclusion

The for loop in Go is a powerful tool for iterating over arrays. Using either index-based iteration or the range keyword, you can efficiently access and manipulate array elements.