Find · Software Engineering Wiki

Returns the value of the first element in the provided collection that satisfies the provided testing function.

Implement an appropriate function for each type.
Use range to iterate over elements in the given collection, using f to determine if the element matches.
Return the value of the first matching element and nil if a value is found.
Use fmt.Errorf() to generate an appropriate error and return it alongsie a zero value for the type.

import "fmt"

func FindInt(arr []int, f func(int) bool) (int, error) {
	for _, v := range arr {
		if f(v) {
			return v, nil
		}
	}
	return 0, fmt.Errorf("No matches found")
}
func FindFloat64(arr []float64, f func(float64) bool) (float64, error) {
	for _, v := range arr {
		if f(v) {
			return v, nil
		}
	}
	return 0.0, fmt.Errorf("No matches found")
}
func FindBool(arr []bool, f func(bool) bool) (bool, error) {
	for _, v := range arr {
		if f(v) {
			return v, nil
		}
	}
	return false, fmt.Errorf("No matches found")
}
func FindString(arr []string, f func(string) bool) (string, error) {
	for _, v := range arr {
		if f(v) {
			return v, nil
		}
	}
	return "", fmt.Errorf("No matches found")
}

FindInt([]int{1, 1, 2}, func(x int) bool { return x%2 == 0 }) // 2 nil
FindFloat64([]float64{4.0, 6.0}, func(x float64) bool { return x%2.0 == 1.0 }) // 0.0 "No matches found"