main.py

from flask import Flask, render_template, request
import pandas as pd
import numpy as np
from scipy import stats
import os.path
from flask import Markup

app = Flask(__name__)
app.config["DEBUG"] = True

# constructor - load once (otherwise setup a local csv copy to save on bandwidth usage)
BASE_DIR = os.path.dirname(os.path.abspath(__file__))

src = os.path.join(BASE_DIR, 'WHOSIS_000001,WHOSIS_000015.csv')
who_list = pd.read_csv(src)
who_list = who_list[['GHO (DISPLAY)', 'YEAR (CODE)' , 'COUNTRY (DISPLAY)', 'SEX (DISPLAY)', 'Numeric']]
who_list['COUNTRY (DISPLAY)'] = [ctry.title() for ctry in who_list['COUNTRY (DISPLAY)'].values]
country_list = sorted(set(who_list['COUNTRY (DISPLAY)'].values))

def get_life_expectancy(age, country, sex):
    # pull latest entries for birth and 60 years
    sub_set = who_list[who_list['COUNTRY (DISPLAY)'].str.startswith(country, na=False)]
    sub_set = sub_set[sub_set['SEX (DISPLAY)'] == sex]
    sub_set = sub_set.sort_values('YEAR (CODE)', ascending=False)
    sub_set_birth = sub_set[sub_set['GHO (DISPLAY)'] == 'Life expectancy at birth (years)']
    sub_set_60 = sub_set[sub_set['GHO (DISPLAY)'] == 'Life expectancy at age 60 (years)']
    # not all combinations exsits so check that we have data for both
    if len(sub_set_birth['Numeric']) > 0 and len(sub_set_birth['Numeric']) > 0:
        # create data set with both points as shown in first example
        lf_at_birth = sub_set_birth['Numeric'].values[0]
        lf_at_60 = sub_set_60['Numeric'].values[0]
        # model
        slope, intercept, r_value, p_value, std_err = stats.linregress([0,60],[lf_at_birth, lf_at_60])
        # predict for the age variable
        return(np.ceil(slope * age + intercept))
    else:
        return None


@app.route('/', methods=['POST', 'GET'])
def interact_life_expectancy():
    # select box defaults
    default_age = 'Select Age'
    selected_age = default_age
    default_sex = 'Select Gender'
    selected_sex = default_sex
    default_country = 'Select Country'
    selected_country = default_country
    # data carriers
    string_to_print = ''
    healthy_image_list = []
    if request.method == 'POST':
        # clean up age field
        selected_age = request.form["age"]
        if (selected_age == default_age):
            selected_age = int(29)
        else:
            selected_age = selected_age

        # clean up sex field
        selected_sex = request.form["sex"]
        if (selected_sex == default_sex):
            selected_sex = 'Both sexes'

        # clean up country field
        selected_country = request.form["country"]
        if (selected_country == default_country):
            selected_country = 'United States Of America'

        # estimate lifespan
        current_time_left = get_life_expectancy(age=int(selected_age), country=selected_country, sex=selected_sex)

        if (current_time_left is not None):
            # create output string
            string_to_print = Markup("You have <font size='+10'>" + str(int(np.ceil(current_time_left))) + "</font> healthy years left to live!")
        else:
            string_to_print = Markup("Error! No data found for selected parameters")
            current_time_left = 1

        # healthy years
        healthy_image_list = []
        # squat.png, stretch.png, jog.png
        healthy_years_left = int(np.ceil(current_time_left))
        image_switch=0
        if (healthy_years_left > 0):
            for y in range(healthy_years_left):
                if image_switch == 0:
                    healthy_image_list.append('static/images/Cycling.png')
                elif image_switch == 1:
                    healthy_image_list.append('static/images/Jogging.png')
                elif image_switch == 2:
                    healthy_image_list.append('static/images/JumpingJack.png')
                elif image_switch == 3:
                    healthy_image_list.append('static/images/Stretching.png')
                elif image_switch == 4:
                    healthy_image_list.append('static/images/WeightLifting.png')
                else:
                    healthy_image_list.append('static/images/Yoga.png')
                    image_switch = -1
                image_switch += 1
    return render_template('time.html',
                            country_list = country_list,
                            default_country = selected_country,
                            default_age=selected_age,
                            default_sex=selected_sex,
                            string_to_print = string_to_print,
                            healthy_image_list = healthy_image_list)
if __name__ == '__main__':
    app.run(host='0.0.0.0',port=5000, debug=True)