Using Streamlit widgets in a multi-column table format (dynamic update)

multi-column-widgets-with-continuous-update.py

# My solution for: https://discuss.streamlit.io/t/how-to-update-st-columns/25501/3
# This uses a button callback to report the enroll action. Notice how all the widget keys are
# generated so they are unique. To deal with being able to edit the values from their defaults, 
# and report on them correctly, I am printing out the widgets’ session state values.
# UPDATE: Added continuous update of the students list

import streamlit as st
from dataclasses import dataclass
import time
import random
import numpy as np

state = st.session_state
if 'message' not in state:
    state.message = 'No student enrolled'

st.info(state.message)

@dataclass
class Student():
    def __init__(self, name, age, course):
        self.name = name
        self.age = age
        self.course = course

    def __repr__(self) -> str:
        return f'|Name: {self.name}, Age: {self.age}, Course: {self.course}|'

def get_students():
    num_students = random.randint(1,10)
    print('', num_students)
    rnd_ages = [random.randint(18,60) for _ in range(num_students)]
    print('', rnd_ages)
    rnd_course_stage = [c for c in np.random.permutation([100, 101, 200, 201, 300, 301, 400, 401, 500, 501])]
    print('', rnd_course_stage)
    rnd_course_subj = [c for c in np.random.permutation(['CS', 'DS', 'CS', 'DS', 'SS', 'CS', 'DS', 'CS', 'DS', 'SS'])]
    print('', rnd_course_subj)
    rnd_courses = [f'{sub}{stage}' for sub, stage in zip(rnd_course_subj, rnd_course_stage)]
    print('', rnd_courses)
    students = [Student(name=f'Student {i}', age=rnd_ages[i], course=rnd_courses[i]) for i in range(num_students)]
    print(students)
    return students

def _enroll_cb(student, index):
    name = state[f'{student.name}_{index}']
    age = state[f'{student.age}_{index}']
    course = state[f'{student.course}_{index}']
    state.message = f'Enrolled: {name}, {age}, {course}'

c1, c2, c3, c4 = st.columns([1,1,1,1])
c1.subheader('Student')
c2.subheader('Age')
c3.subheader('Course')
c4.subheader(' ')

for index, student  in enumerate(get_students(), start=0):
        with c1:
            st.text_input('', student.name, key=f'{student.name}_{index}')
        with c2:
            st.number_input('', min_value=18, max_value=60, value=student.age, key=f'{student.age}_{index}')
        with c3:
            st.text_input('', student.course, key=f'{student.course}_{index}')
        with c4:
            st.write(' ')
            st.button('enroll', on_click=_enroll_cb, args=(student,index), key= f'enroll_{index}')

time.sleep(3)
st.experimental_rerun()