# How to get on\_change callback func work with data\_editor **URL:** \ **Category:** Using Streamlit\ **Tags:** data\_editor, session-state, discussion\ **Created:** [November 21, 2024, 11:03pm UTC](https://discuss.streamlit.io/t/how-to-get-on-change-callback-func-work-with-data-editor/86141 "2024-11-21T23:03:53Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![serdar\_bay](https://sea2.discourse-cdn.com/streamlit/user_avatar/discuss.streamlit.io/serdar_bay/32/52473_2.png) [@serdar\_bay](https://discuss.streamlit.io/u/serdar_bay)\ **Post date:** [November 21, 2024, 11:03pm UTC](https://discuss.streamlit.io/t/how-to-get-on-change-callback-func-work-with-data-editor/86141/1 "2024-11-21T23:03:53Z")
Hi, I am trying to use on\_change callback function within data\_editor. I can’t seem to get my table updated when I edit the editable fields on the table. My expectation is as soon as I edit the data the table should update in place. Here is my code that I could not get working correctly for me. Currently, when I change data, nothing happens (i.e the prices do not get updated). > ``` > if final_dfs: > st.session_state.final_df = pd.concat(final_dfs, ignore_index=True) > > # Add default values and extra columns > if "Markup, %" not in st.session_state.final_df.columns: > st.session_state.final_df["Markup, %"] = 30 > if "External margin, %" not in st.session_state.final_df.columns: > st.session_state.final_df["External margin, %"] = 50 > if "Select" not in st.session_state.final_df.columns: > st.session_state.final_df["Select"] = False > > # Define a callback function to recalculate the prices > def recalculate_prices(): > st.session_state.final_df = calculate_price_with_markup(st.session_state.final_df) > st.session_state.final_df = calculate_total_price(st.session_state.final_df) > st.session_state.final_df = calculate_final_base_margin(st.session_state.final_df) > > # Rearrange the column sequence > desired_order = [ > "part_id", > "diameter_in", > "Total Cost (USD)", > "Markup, %", > "Price with markup (USD)", > "External margin, %", > "Total price (USD)", > "Final base margin, %", > "Select" > ] > st.session_state.final_df = st.session_state.final_df[desired_order] > > # Initial calculation of prices > recalculate_prices() > > # Define the column configuration > column_config = { > "part_id": st.column_config.TextColumn( > "Part ID", > disabled=True, > ), > "diameter_in": st.column_config.NumberColumn( > "Diameter", > disabled=True, > ), > "Total Cost (USD)": st.column_config.NumberColumn( > "Total Cost (USD)", > disabled=True, > ), > "Markup, %": st.column_config.NumberColumn( > "Markup, %", > ), > "External margin, %": st.column_config.NumberColumn( > "External margin, %", > > ), > "Price with markup (USD)": st.column_config.NumberColumn( > "Price with markup (USD)", > disabled=True, > > ), > "Total price (USD)": st.column_config.NumberColumn( > "Total price (USD)", > disabled=True, > ), > "Final base margin, %": st.column_config.NumberColumn( > "Final base margin, %", > disabled=True, > ), > > "Select": st.column_config.CheckboxColumn("Select"), > } > > # Display the data editor > edited_df = st.data_editor( > st.session_state.final_df, > key="data_editor", > hide_index=True, > column_config=column_config, > on_change=recalculate_prices, > ) > > ``` ---
**Author:** ![Encrypt](https://sea2.discourse-cdn.com/streamlit/user_avatar/discuss.streamlit.io/encrypt/32/52088_2.png) [@Encrypt](https://discuss.streamlit.io/u/Encrypt)\ **Post date:** [November 23, 2024, 8:49am UTC](https://discuss.streamlit.io/t/how-to-get-on-change-callback-func-work-with-data-editor/86141/2 "2024-11-23T08:49:51Z")
The `on_change` callback lacks access to the most recent edited data values. Consequently, I have implemented a manual update procedure for the session state data frame after an edit, ensuring that the prices are recalculated accordingly. ```auto import streamlit as st import pandas as pd # Placeholder functions for price calculations def calculate_price_with_markup(df): df["Price with markup (USD)"] = df["Total Cost (USD)"] * (1 + df["Markup, %"] / 100) return df def calculate_total_price(df): df["Total price (USD)"] = df["Price with markup (USD)"] * (1 + df["External margin, %"] / 100) return df def calculate_final_base_margin(df): df["Final base margin, %"] = (df["Total price (USD)"] - df["Total Cost (USD)"]) / df["Total price (USD)"] * 100 return df # Assuming final_dfs is a list of DataFrames final_dfs = [ pd.DataFrame({ "part_id": ["A1", "B1", "C1"], "diameter_in": [1.0, 2.5, 3.0], "Total Cost (USD)": [10, 20, 30], }), pd.DataFrame({ "part_id": ["D1", "E1", "F1"], "diameter_in": [4.0, 5.5, 6.0], "Total Cost (USD)": [40, 50, 60], }) ] if final_dfs: # Define a callback function to recalculate the prices def recalculate_prices(): print("Recalculating prices...") st.session_state.final_df = calculate_price_with_markup(st.session_state.final_df) st.session_state.final_df = calculate_total_price(st.session_state.final_df) st.session_state.final_df = calculate_final_base_margin(st.session_state.final_df) # Rearrange the column sequence desired_order = [ "part_id", "diameter_in", "Total Cost (USD)", "Markup, %", "Price with markup (USD)", "External margin, %", "Total price (USD)", "Final base margin, %", "Select" ] st.session_state.final_df = st.session_state.final_df[desired_order] # Initialize the final DataFrame if not already present if 'final_df' not in st.session_state: st.session_state.final_df = pd.concat(final_dfs, ignore_index=True) # Add default values and extra columns if "Markup, %" not in st.session_state.final_df.columns: st.session_state.final_df["Markup, %"] = 30 if "External margin, %" not in st.session_state.final_df.columns: st.session_state.final_df["External margin, %"] = 50 if "Select" not in st.session_state.final_df.columns: st.session_state.final_df["Select"] = False recalculate_prices() # Define the column configuration column_config = { "part_id": st.column_config.TextColumn( "Part ID", disabled=True, ), "diameter_in": st.column_config.NumberColumn( "Diameter", disabled=True, ), "Total Cost (USD)": st.column_config.NumberColumn( "Total Cost (USD)", disabled=True, ), "Markup, %": st.column_config.NumberColumn( "Markup, %", ), "External margin, %": st.column_config.NumberColumn( "External margin, %", ), "Price with markup (USD)": st.column_config.NumberColumn( "Price with markup (USD)", disabled=True, ), "Total price (USD)": st.column_config.NumberColumn( "Total price (USD)", disabled=True, ), "Final base margin, %": st.column_config.NumberColumn( "Final base margin, %", disabled=True, ), "Select": st.column_config.CheckboxColumn("Select"), } # Display the data editor edited_df = st.data_editor( st.session_state.final_df, key="data_editor", hide_index=True, column_config=column_config, ) # Check if the data has been edited and recalculate prices if not edited_df.equals(st.session_state.final_df): st.session_state.final_df = edited_df recalculate_prices() # Trigger a rerun to update the displayed data st.rerun() ``` ---
**Author:** ![system](https://global.discourse-cdn.com/streamlit/original/3X/c/f/cf4c2ee0d938358f82448c5fe4b9c3c91d7ce19c.svg) [@system](https://discuss.streamlit.io/u/system)\ **Post date:** [May 22, 2025, 8:50am UTC](https://discuss.streamlit.io/t/how-to-get-on-change-callback-func-work-with-data-editor/86141/3 "2025-05-22T08:50:19Z")
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