Find the first element in an array that matches the search criteria.

FinderExample.Go

package main

import (
	"reflect"
	  "log"
)

type Part struct {
  Id int
  UPC string
  Desc string
}


// Find the first struct in an array that matches search criteria.
// Search Criteria  includes the field on the struct you are searching and the value of field you are searching.
// For example: You could pass in an array of Parts. You want to find the first part with an ID of 11000. Method call would be something like:
//
//	var result = finder.FindFirst(listOfParts, "Id", 11000) // the array can be any type, the field is represented by a string, and the value you are searching for can be any type.
//
//  if result != nil {
//		partObj := result.(part) // .(part) casts it to whatever type object you expect to return (same as array type)
// 		log.Println(partObj.UPC) // outputs the UPC for the part with an Id of 11000.
//	}
// This approach is similar to c# LINQ statement: listOfParts.Where(x=>x.Id == 11000).FirstOrDefault()

func FindFirst(arrayToSearch interface{}, field string, value interface{}) (singleObj interface{}) {
	slice := reflect.ValueOf(arrayToSearch)
	vals := make([]reflect.Value, slice.Len(), slice.Len())
	for i := range vals {
		vals[i] = reflect.Indirect(reflect.Indirect(slice.Index(i)))
	}
	for _, t := range vals {
		val := t.FieldByName(field).Interface()
		var stringVal interface{}
		stringVal = value
		if val == stringVal {
			singleObj = t.Interface()
			return
		}
	}
	return
}

func main() {
  var listOfParts []Part

  var partToSearch Part
  partToSearch.Id = 12345
  partToSearch.UPC = "0023423"
  partToSearch.Desc = "awesomeo"

  var partToSearch2 Part
  partToSearch2.Id = 11123
  partToSearch2.UPC = "00Jdl3i8"
  partToSearch2.Desc = "notSoAwesome"

  listOfParts = append(listOfParts, partToSearch, partToSearch2)

  temp := ""
  var result = FindFirst(listOfParts, "Id", 11123)
  if result != nil {
    partObj := result.(Part)
    temp = partObj.UPC
    log.Println("UPC is: " + temp)
  }
}