python3 -m venv ~/.core_ml_demo
source  ~/.core_ml_demo/bin/activate
python3 -m pip install \
pandas==1.1.1 \
scikit-learn==0.19.2 \
coremltools==4.0

import pandas as pd
from sklearn.linear_model import LinearRegression
from sklearn.datasets import load_boston
# Load data
boston = load_boston()
boston_df = pd.DataFrame(boston["data"])
boston_df.columns = boston["feature_names"]
boston_df["PRICE"]= boston["target"]
y = boston_df["PRICE"]
X = boston_df.loc[:,["RM", "AGE", "PTRATIO"]]
# Train a model
lm = LinearRegression()
lm.fit(X, y)

# Convert sklearn model to CoreML
import coremltools as cml
model = cml.converters.sklearn. \
convert(lm,
        ["RM", "AGE", "PTRATIO"],
        "PRICE")
# Assign model metadata
model.author = "Medium Author"
model.license = "MIT"
model.short_description = \
"Predicts house price in Boston"
# Assign feature descriptions
model.input_description["RM"] = \
"Number of bedrooms"
model.input_description["AGE"] = \
"Proportion of units built pre 1940"
model.input_description["PTRATIO"] = \
"Pupil-teacher ratio by town"
# Assign the output description
model.output_description["PRICE"] = \
"Median Value in 1k (USD)"
# Save model
model.save('bhousing.mlmodel')

import SwiftUI
import CoreML
import Foundation
struct ContentView: View {
  @State private var rm = 6.5
  @State private var age = 84.0
  @State private var ptratio = 16.5
  @State private var alertTitle = ""
  @State private var alertMessage = ""
  @State private var showingAlert = false
  var body: some View {
      NavigationView {
        VStack {
        Text("House Attributes")
            .font(.title)
        Stepper(value: $rm, in: 1...10,
                step: 0.5) {
            Text("Rooms: \(rm)")
          }
          Stepper(value: $age, in: 1...100,
              step: 0.5) {
          Text("Age: \(age)")
          }
          Stepper(value: $ptratio, in: 12...22,
              step: 0.5) {
          Text("Pupil-teacher ratio: \(ptratio)")
          }
          .navigationBarTitle("Price Predictor")
          .navigationBarItems(trailing:
              Button(action: predictPrice) {
                  Text("Predict Price")
              }
          )
          .alert(isPresented: $showingAlert) {
              Alert(title: Text(alertTitle),
                    message: Text(alertMessage),
              dismissButton: .default(Text("OK")))
          }
        }
      }
  }
func predictPrice() {
    let model = bhousing()
    do { let p = try
      model.prediction(
          RM: Double(rm),
          AGE: Double(age),
          PTRATIO: Double(ptratio))
        alertMessage = "$\(String((p.PRICE * 1000)))"
      alertTitle = "The predicted price is:"
  } catch {
    alertTitle = "Error"
    alertMessage = "Please retry."
  }
    showingAlert = true
}
}
struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}