[{"id":31,"balance":"$1,137.95","age":24,"eyeColor":"blue","name":"Burris Newton","gender":"male","company":"XOGGLE","email":"burrisnewton@xoggle.com",}]

db.collection.update({},[{"$set":{"gender":{$cond:[{$eq:["$gender","male"]},"H","F"]}}},],{"multi":false,"upsert":false})