Issues Cycling Through Weapons-C#

I am trying to cycle through my weapons using the "F" key on my keyboard using the script below (@nastasache maybe you know how to fix this?). I currently only have two weapons that I'm trying to cycle through but when I run the code below, nothing happens.

 public GameObject[] weapons;

 public int currentWeapon = 0;
 private int nrWeapons;

 void Start () {
     nrWeapons = weapons.Length;

     SwitchWeapon (currentWeapon);
 }
 
 void Update () {
     for (int i = 1; i <= nrWeapons; i++){
         if (Input.GetKeyDown (KeyCode.F + i)) {
             currentWeapon = i - 1;

             SwitchWeapon (currentWeapon);
         }
     }
 }
 void SwitchWeapon (int index){
     for (int i = 0; i < nrWeapons; i++) {
         if (i == index) {
             weapons [i].gameObject.SetActive (true);
         } else {
             weapons [i].gameObject.SetActive (false);
         }
     }
 }

I've tried removing the "+ i" part of the if statement in the Update function so it just reads (KeyCode.F):

     for (int i = 1; i <= nrWeapons; i++){
         if (Input.GetKeyDown (KeyCode.F)) {
             currentWeapon = i - 1;

             SwitchWeapon (currentWeapon);
         }
     }

but this only lets me switch from my primary weapon to my secondary weapon a single time--I am not able to switch back to my primary weapon.

In the meantime I am going to set each weapon to a corresponding alpha key and have it switch that way but I would really love to have it cycle on a single key so if anybody is able to help or has any suggestions I'm all ears.

Thanks!!!