Create columns to a data_editor with data

Using Streamlit
1

Summary

Hello guys, i want to be able to type in a column name using text_input and then press a button for adding that column name as a column to a data_editor without the current data in the data_editor are disappearing.

Steps to reproduce

Code snippet:

def test_columns(col_name):
    first_key = next(iter(st.session_state["cso_df"]))  # Get the first key
    value_count = len(st.session_state["cso_df"][first_key])
    st.session_state["cso_df"][col_name] = [""] * value_count
    st.session_state.add_column = ""

        
def change_state2(edited_df):
    st.session_state["cso_df"] = edited_df


if create_scratch_options == 'create data without using a template':

   create_col = st.sidebar.text_input('add a column', placeholder="type a column name", 
   key="add_column")

   create_col_btn = st.sidebar.button('add the column', on_click=test_columns, args=(create_col,))


   if 'cso_df' not in st.session_state:
      st.session_state["cso_df"] = st.data_editor({'column1': [None],'column2': [None],'column3': [None]}, 
      num_rows='dynamic', use_container_width=True)

   else:
      st.session_state["cso_df"] = st.data_editor(st.session_state["cso_df"], num_rows='dynamic', 
      use_container_width=True, on_change=change_state2, args=(st.session_state["cso_df"],))

Expected behavior:

when i type in a column name and click the add button, i should see a new column being added to the data_editor with empty values, and the existing data i have already typed in to the data_editor should not disappear.

Actual behavior:

whenever i have data in the data_editor and create a new column, the column shows successfully, but all the existing data are being removed. So it just end up being an empty dataframe also containing the new column.

Debug info

  • Streamlit version: Streamlit, version 1.23.1
  • Python version: Python 3.9.5

Additional information

This issue definitely occur because of the architecture of how the data_editor is designed. Since it seems like the data_editor is not updated each time i add some data to it. I have also noted that if i add a column name then remove it again, press the background of my app(so the page loads) then type the column name again, and press the add button, then it works.

2

finally got it working.

The solution was to add the below line before adding columns to the st.data_editor:

st.session_state.some_key = edited_df

where st.session_state.some_key is the input df to st.data_editor and edited_df is the value of the st.data_editor.

3

This topic was automatically closed 2 days after the last reply. New replies are no longer allowed.