swift3 - if statement to load marker image swift 3 mapbox ios sdk -

i using swift 3. when hit specific string while going through loop of iterated geojson data (jsonobj[i]) need call right image file. able return right pass type , load markers in map correctly. can't seem figure out how app load right color per marker type.

i have tried switch statement no luck. have looked @ if statement documentation among many other stack overflow posts , tutorials.

  var pass : string?   var brown = uiimage(named: "brown.png")   var purple = uiimage(named: "purple.png")   var green = uiimage(named: "green.png")   var image : uiimage? 

the block of code below in loop. each record iterated through loads marker title , subtitle. code reads first marker color "purple" , loads points purple marker instead of selecting based on pass1, pass2 returned.

  var pass = jsonobj[i]["properties"]["pass"]                       print("propertiespassstring: ", pass)                      if pass == "pass1" {                         print("pass1!")                         image = purple                      }                     else if pass == "pass2" {                         print("pass2")                         image = brown                      }                     else if pass == "" {                         print("pass3")                         image = green                      } 

here func loads marker, not sure if needed applies or loads "image" or custom marker/variable in each iteration of loop. largely copy , pasted mapbox ios sdk

func mapview(_ mapview: mglmapview, annotationcanshowcallout annotation: mglannotation) -> bool {     // try show callout when annotation tapped.     return true     }  func mapview(_ mapview: mglmapview, imagefor annotation: mglannotation) -> mglannotationimage? {     // try reuse existing ‘point’ annotation image, if exists.     var annotationimage = mapview.dequeuereusableannotationimage(withidentifier: "point")      if annotationimage == nil {         print("annotationimage")          image = image?.withalignmentrectinsets(uiedgeinsets(top: 0, left: 0, bottom: (image?.size.height)!/2, right: 0))         // initialize ‘point’ annotation image uiimage loaded.         annotationimage = mglannotationimage(image: image!, reuseidentifier: "point")         }     //image = nil     return annotationimage!      } 

if have advice/suggestions newer programmer in swift 3 appreciate it. i've been stuck on several days now. still learning how utilize stack overflow please let me know if there better way go posting question, open constructive critiques.