Creating Dynamic Text of date time that changes every second in Streamlit - streamlit

Question

I would like to display the output of datatime.now being refreshed every 1 second on the streamlit webui.
from datetime import datetime
datetime.now()
# print this output every one second
datetime.datetime(2020, 5, 19, 4, 22, 40, 921985)
What I have already tried
#!/usr/bin/env python3
import streamlit as st
from datetime import datetime
timenow = str(datetime.now())
st.write(timenow)

Answer 1

I suppose it depends on whether you need exactly one second resolution or not, but the solution is approximately:
import time
from datetime import datetime
import streamlit as st
t = st.empty()
while True:
t.markdown("%s" % str(datetime.now()))
time.sleep(1)
The while loop keeps the process going forever. By having the st.empty() call outside of the loop, we keep modifying the t variable. On each loop repetition, the value for the markdown string gets overwritten by the datetime.now() argument.

Answer 2

Display Time With Infinite While Loop AT END OF Streamlit Code
The placeholder code in the while loop is likely not needed. Using t.write or t.markdown as #Randy Zwitch does is fine. I just wanted to show that IF you use this while look approach, put it at the end of your streamlit script. Even then, watch how the time is interrupted when the button state is updated in the code above the while loop.
import streamlit as st
from datetime import datetime
import time
# Section 1
button = st.button('Button')
button_placeholder = st.empty()
button_placeholder.write(f'button = {button}')
time.sleep(2)
button = False
button_placeholder.write(f'button = {button}')
# Section 2
time_placeholder = st.empty()
while True:
timenow = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
time_placeholder.write(timenow)
time.sleep(1)