give a function to flatten an array; if it has nils, remove the nils before flattening. if it is all nils, return empty array. in go

Here is a possible implementation in Go using recursion:

main.go
package main

import (
	"fmt"
)

func flattenArray(arr []interface{}) []interface{} {
	flattened := make([]interface{}, 0)
	for _, element := range arr {
		if element == nil {
			continue
		}
		switch element := element.(type) {
		case []interface{}:
			flattened = append(flattened, flattenArray(element)...)
		default:
			flattened = append(flattened, element)
		}
	}
	return flattened
}

func main() {
	arr := []interface{}{
		1, nil, []interface{}{
			2, nil, []interface{}{
				3, nil,
			},
		},
		nil, []interface{}{
			nil, nil,
		},
	}

	flattened := flattenArray(arr)
	fmt.Println(flattened)
}
604 chars
38 lines

In this implementation, the flattenArray function takes an array of interface{} type as input and recursively flattens it while removing nil values. The flattened array is built using a for loop, checking each element in the input array. If an element is nil, it is skipped. If an element is another array, the function is called recursively on that array and the flattened result is appended to the final flattened array. If an element is not nil or an array, it is directly appended to the final flattened array.

In the main function, you can see an example usage of the flattenArray function with a sample input array. The resulting flattened array is then printed.

Output:

main.go
[1 2 3]
8 chars
2 lines

Note: This implementation assumes that the input array only contains valid primitive values or nested arrays of the interface{} type.