streamlit_app.py

# import the streamlit library
import streamlit as st

# give a title to our app
st.title('Welcome to BMI Calculator')

# TAKE WEIGHT INPUT in kgs
weight = st.number_input("Enter your weight (in kgs)")

# TAKE HEIGHT INPUT
# radio button to choose height format
status = st.radio('Select your height format: ', ('cms', 'meters', 'feet'))

# compare status value
if (status == 'cms'):
  # take height input in centimeters
  height = st.number_input('Centimeters')

  try:
    bmi = weight / ((height / 100)**2)
  except:
    st.text("Enter some value of height")

elif (status == 'meters'):
  # take height input in meters
  height = st.number_input('Meters')

  try:
    bmi = weight / (height**2)
  except:
    st.text("Enter some value of height")

else:
  # take height input in feet
  height = st.number_input('Feet')

  # 1 meter = 3.28
  try:
    bmi = weight / (((height / 3.28))**2)
  except:
    st.text("Enter some value of height")

# check if the button is pressed or not
if (st.button('Calculate BMI')):

  # print the BMI INDEX
  st.text("Your BMI Index is {}.".format(bmi))

  # give the interpretation of BMI index
  if (bmi < 16):
    st.error("You are Extremely Underweight")
  elif (bmi >= 16 and bmi < 18.5):
    st.warning("You are Underweight")
  elif (bmi >= 18.5 and bmi < 25):
    st.success("Healthy")
  elif (bmi >= 25 and bmi < 30):
    st.warning("Overweight")
  elif (bmi >= 30):
    st.error("Extremely Overweight")