swift - How to write JSON mixed mode data? -

i want write combination of dictionary , data array.

my data looks this

the function use

  func writejsondata()   {     var error: nserror?     var filename:string = "testwrite.json"     var dict:nsmutabledictionary = ["3dmodel":"model_student_v3", "3ddata":"testdata file", "3dcolors":"color file name"]      var myarray:[float] = [1.0,-0.13131,12.0]      let dirpaths = nssearchpathfordirectoriesindomains(       nssearchpathdirectory.documentdirectory,       nssearchpathdomainmask.userdomainmask,       true     )     let docsdir = dirpaths[0] string     let filepath = docsdir.stringbyappendingpathcomponent(filename)      if let outputjson = nsoutputstream(tofileatpath: filepath, append: false)     {       outputjson.open()       nsjsonserialization.writejsonobject(dict, tostream: outputjson, options: nsjsonwritingoptions(), error: &error)       nsjsonserialization.writejsonobject(myarray, tostream: outputjson, options: nsjsonwritingoptions(), error: &error)       outputjson.close()     }   } 

of course json not valid there no name attach array.

> { >     "3dmodel": "model_student_v3", >     "3dcolors": "color file name", >     "3ddata": "testdata file" }[ >     1, >     -0.13131, >     12 ] 

it should like

{     "3dmodel": "model_student_v3",     "3dcolors": "color file name",     "3ddata": "testdata file",     "data": [         1,         -0.13131,         12     ] } 

just use dict ["data"] = myarray , write dict.