Please help me with some questions about selectbox, thank you

I need the selectbox default value to be a string such as: please select and then the data list to be all values of pd.DataFrame. How do I implement this function?

list_ip2 = pd.DataFrame(get_list2())
option = st.selectbox('plese select ',option=list_ip2)

I wanted to add a default boot string to the selectbox to help the user click on the corresponding value, but when I used the DataFrame, I didn’t get what I wanted

After the program runs, the selectbox automatically executes the value of the first line. I want the user to select the corresponding option before executing it. For example, I want the effect to be as follows:

option = st.selectbox('select',option='Please select',pd.DataFrame())