Creating a property prediction App

Using Python and Streamlit to create a property price app using machine learning


Thomas H. Simm


This is an app for predicting house prices in Swansea using Streamlit

The app uses the following for predictions:

  1. House price sales (price and date)
  2. Name of street and number
  3. Location of property (Lattitude and Longitude)
  4. Data on Census regions

More details of the prediction side of the app, using Random Forrests and neural networks, is dealt with here.

A video of the app is shown below or can be accessed via property app

The intention of the app is to provide a simple user interface to allow price predictions

The Python Script for the App

Loading the data

The following function is used to load the data.

The data consists of 4 parts: 1. m = the model (this is by far the biggest part in terms of data size) 1. to = a data frame object of the house data 1. xsAll = this is a form of ‘to’ used by the model (the input values of the model) 1. yAll = a form of ‘to’ the values the model is trying to predict (house price values)

The data is saved as a pickle file in a Jupyter Notebook, then uploaded to googledrive as filesize has to be less than 100 Mb on GitHub., output) downloads the data from GoogleDrive

@st.cache(allow_output_mutation=True) This line at the top of the python file means the data is cached and don’t need to keep loading it

def load_data():
    Loads the data
    import gdown
    url = ''
    output = 'one1.pkl', output)

    cda = os.getcwd()
    with open('one1.pkl', 'rb')as f: 
        m2, to2, xsAll2, yAll2 = pickle.load(f)
    return m2, to2, xsAll2, yAll2
data_load_state = st.text('Loading data...')
m1, to1, xsAll1, yAll1=load_data()
data_load_state.text("Loaded data (using st.cache)")

Updating data so prediction is for today

The following function changes the date of sale details for each property so that they are today’s date

def add_datepart(df, field_name, prefix=None, drop=True, time=False):

Getting the predictions

The following function takes the address selected and outputs the predicted property price


Help with reducing code for selecting data

The following function is used to allow to select different details from the dataframes. Really just a function to get around the slightly unusual way data is selected in ‘to’ and dataFrames

def doSelect(typee,option2,typeeOut,toTEMP):

The user interface parts of the app

optionSELECT = st.sidebar.selectbox( 'Select how to search', choice)

This is a select box loacted in the LHS sidebar. The options for the user are as follows and choice dictates what boxes they see:

choice=['Post Code','Region', 'Street']

For example if ‘Post code’ is selected the folowing selectbox is shown with all post code options for first part of the postcode:

option2 = st.sidebar.selectbox( 'Select Postcode', indexPCSA)

Whatever option selected the individual address must be selected:

address = st.sidebar.selectbox( 'Select Address', AdSel)

Predictions and Output

Once the address is selected, teh predictions are found by calling the prediction function:

Pri1, Pri2, typa=get_predTodayNotExact(m,address,(to),(xsAll),(yAll))

And then displayed in the main screen with the following code:

'You selected: ', option2, 'and', address

'Property type is ',typa

stra = 'The predicted price is: ' st.subheader(stra) st.header('£'+ str(Pri1[0])+'k')

Creating the App

The Python .py file along with a requirements file are uploaded to a GitHub repository. The one for this is at git hub PropertyStreamlit

The requirements file includes all the modules not included in python that need to be loaded. For this function the file is as follows:


Then simply log into Streamlit select the repository and the python file and hit go to get the app working

Full Python function

import streamlit as st
# To make things easier later, we're also importing numpy and pandas for
# working with sample data.
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
import os
import pickle
import copy
from sklearn.ensemble import RandomForestRegressor

st.title('Swansea Property Price Predictor')

def load_data():
    Loads the data
    import gdown
    url = ''
    output = 'one1.pkl', output)

    cda = os.getcwd()
    with open('one1.pkl', 'rb')as f: 
        m2, to2, xsAll2, yAll2 = pickle.load(f)
    return m2, to2, xsAll2, yAll2
data_load_state = st.text('Loading data...')
m1, to1, xsAll1, yAll1=load_data()
data_load_state.text("Loaded data (using st.cache)")

def add_datepart(df, field_name, prefix=None, drop=True, time=False):
    "Helper function that adds columns relevant to a date in the column `field_name` of `df`."
    import re
    import pandas as pd
    import numpy as np
    def ifnone(a, b):
        "`b` if `a` is None else `a`"
        return b if a is None else a
    def make_date(df, date_field):
        "Make sure `df[date_field]` is of the right date type."
        field_dtype = df[date_field].dtype
        if isinstance(field_dtype, pd.core.dtypes.dtypes.DatetimeTZDtype):
            field_dtype = np.datetime64
        if not np.issubdtype(field_dtype, np.datetime64):
            df[date_field] = pd.to_datetime(df[date_field], infer_datetime_format=True)
    make_date(df, field_name)
    field = df[field_name]
    prefix = ifnone(prefix, re.sub('[Dd]ate$', '', field_name))
    attr = ['Year', 'Month', 'Week', 'Day', 'Dayofweek', 'Dayofyear', 'Is_month_end', 'Is_month_start',
            'Is_quarter_end', 'Is_quarter_start', 'Is_year_end', 'Is_year_start']
    if time: attr = attr + ['Hour', 'Minute', 'Second']
    # Pandas removed `dt.week` in v1.1.10
    week = field.dt.isocalendar().week.astype( if hasattr(field.dt, 'isocalendar') else field.dt.week
    for n in attr: df[prefix + n] = getattr(field.dt, n.lower()) if n != 'Week' else week
    mask = ~field.isna()
    df[prefix + 'Elapsed'] = np.where(mask,field.values.astype(np.int64) // 10 ** 9,np.nan)
    if drop: df.drop(field_name, axis=1, inplace=True)
    return df

def get_predTodayNotExact(m,address,toTEMP,xs_final,y):
    Given model m, address, initial pd of houses to, and adjusted pd xs_final
    output is house price prediction
    import copy
    # convert to current date
    colsNoDate=['Type', 'Index of Multiple Deprivation', 'Latitude',
                'Average Income', 'Longitude', 'Postcode', 'Introduced', 'Address',
    xsNoDate['Date'] = pd.to_datetime("today")
    xsNoDate = add_datepart(xsNoDate, 'Date')

    # each address has a unique number
    # findwhich number is address give (take 1st if more than 1)
        ii=[ii for ii,aa1 in enumerate(aa) if aa1== address][0]
        # 1 address can have multiple sales so we need index in dataframes

        preda = np.round( np.exp( m.predict(xs_finalTEMP.loc[ii:ii]) )/1000 ,1)
        prev = np.round( np.exp(y.loc[ii])/1000 ,1)
        ii=[ii for ii,aa1 in enumerate(aaStreet) if aa1== Street][0]
        xsTemp=copy.copy( xs_finalTEMP[xs_finalTEMP['Street']==ii] )
        # find nearest house by houseno

        # get index of the nearest house

        ii=[ii for ii,aa1 in enumerate(xsTemp.HouseNo) if aa1== yo][0]
        # If want to change house type
#         xsTemp.loc[ii:ii,'Type']=2
#         print(xsTemp.loc[ii:ii,'Type'])
#         print(xsTemp.loc[ii:ii])
        preda = np.round( np.exp( m.predict(xsTemp.loc[ii:ii]) )/1000 ,1)[0]
    return preda, prev, typa

def doSelect(typee,option2,typeeOut,toTEMP):
        # this finds index of postcode for example SA1 0EA = 62
        indexPC1=[ita for ita,ij in enumerate(streetAll) if ij==option2][0]

        # finds all indexes of addresses with given post code index 
        indexAdds=[ita for ita, ij in enumerate(toTEMP[typee]) if ij==indexPC1]

        # Find address index numbers for those given above

        # Convert these to actual addresses
        # unique values
        return AdSel

pcodesSA=['SA1', 'SA2', 'SA3', 'SA4', 'SA5', 'SA6', 'SA7', 'SA8',          
          'SA9', 'SA10' ,'SA11', 'SA12', 'SA13', 'SA14','SA15','SA18']

choice=['Post Code','Region', 'Street']

# These are the list of all addresses etc by actual name

# An optionbox- Select How search
optionSELECT = st.sidebar.selectbox(
    'Select how to search',

if optionSELECT=='Post Code':
    # An optionbox- Select Postcode Start e.g. SA1
    option = st.sidebar.selectbox(
        'Select Area',

    # Select Postcode All

    # This finds a set of postcodes given by optionbox
    indexPCSA=[ij for ij in pcAll if ij.split(' ')[0]==option]

    # optionbox to select particular postcode 
    # Outcome e.g. SA1 0EA
    option2 = st.sidebar.selectbox(
        'Select Postcode',

    AdSel = doSelect(typee='Postcode',option2=option2,typeeOut='Address',toTEMP=(to))

elif optionSELECT=='Region':

    option2 = st.sidebar.selectbox(
         'Select Region',
    StreetSel = doSelect(typee='Region',option2=option2,typeeOut='Street',toTEMP=(to))
    option3 = st.sidebar.selectbox(
         'Select Street',
    AdSel = doSelect(typee='Street',option2=option3,typeeOut='Address',toTEMP=(to))

elif optionSELECT=='Street':

    option2 = st.sidebar.selectbox(
         'Select Street',
    AdSel = doSelect(typee='Street',option2=option2,typeeOut='Address',toTEMP=(to))

address = st.sidebar.selectbox(
    'Select Address',

Pri1, Pri2, typa=get_predTodayNotExact(m,address,(to),(xsAll),(yAll))

#tell user what they selected
'You selected: ', option2, 'and', address
'Property type is ',typa

stra = 'The predicted price is: '
st.header('£'+ str(Pri1[0])+'k')