Save date when rerunning whole script

🎈 Using Streamlit
1

hi,
i am new to Pyhton and Streamlit so i would be greatfull for a push in the right direction.
Also i might lack vocabulary so i try to explain what i am looking for.

I got a Pyhtonscript with Streamlit running that reads multiple CSV Files that are saved in DataFrames.
Then the user can select with a dropdown selection one entry and with a datepicker a second.
Calculations are done according to the selection.

Now i want to save the data with calculations in a dataFrame so i can at the end of the session save it to CSV (Basicaly a log file of all selections with calculation results)

for this i made a button. When i push this button the selection is appended to the DataFrame.

However everytime the selection changes, the whole script reruns, essentially wiping all previous data.
How can i make permanent variables.
Or can you just make sections of the script that shoudl rerun?

kind regards

2

data procing should finished by python script, the result will not change again after previous action is done.
you can see the result through the AgGrid
for example:

import streamlit as st
from st_aggrid import AgGrid
import pandas as pd

import base64
from io import BytesIO
def to_excel(df):
output = BytesIO()
writer = pd.ExcelWriter(output, engine=‘xlsxwriter’)
df.to_excel(writer, sheet_name=‘Sheet1’)
writer.save()
processed_data = output.getvalue()
return processed_data
def get_table_download_link(df):
“”“Generates a link allowing the data in a given panda dataframe to be downloaded
in: dataframeout: href string“””

val = to_excel(df)
b64 = base64.b64encode(val) # val looks like b’…’
return f’Download csv file’ # decode b’abc’ => abc

df=pd.read_csv("example.csv")
AgGrid(df,fit_columns_on_grid_load=True)
st.markdown(get_table_download_link(df), unsafe_allow_html=True)
3

hmm, im not sure i completely understand this.

you write everything to a xls and then read it again.

this could work, but i dont want to write to disk yet. i want to make maybe a couple selections, store them in a Dataframe and then push a button → run some code, check for duplicates, and then Save to CSV

4

this is a section of my code where i would to “store” the data from abfrage in log

 #dictionary with data from selectionbox
    ab = {"K-Nummer": [knummer], "Date": [date_near],"Basis": [lme_basis],"LME": [lme_option], "MTZ": [mtz_option]}

log = pd.DataFrame() #initialize logfile for this session
abfrage = pd.DataFrame(ab) #generate the entry from selection after using st.selectbox,...

if st.button('Speichere Daten'):    
    st.write('gespeichert')
    log = log.append(abfrage)     #if button is pushed append to log
    st.text(log)
else:
    st.write('nicht gespeichert')

st.text(abfrage)