Issue in rerunning file_uploader()

🎈 Using Streamlit
1

i just installed the latest version of streamlit.

And i am facing the issue in uploading a csv file from local machine through file_uploader and converting it into a pandas data frame using pd.read_csv(). be low is my code.
Please suggest what am i missing here

def csv_test_input(df_train):
    """ Function to take File based inputs for Network parameter """
    uploaded_file = st.sidebar.file_uploader("Telecom Network Test-Data", type="csv")

    if uploaded_file is None:
        return None

    text_io = io.TextIOWrapper(uploaded_file)

    inputDF = pd.read_csv(text_io)

    return inputDF

on the first run everythings works fine, but i am getting error on rerun of the app.
Error that i am getting is
ValueError: I/O operation on closed file.
at line text_io = io.TextIOWrapper(uploaded_file)

Can you let me know how to fix this issue.

-Irfan

2

It looks like you need to reset your buffer with text_io.seek(0) after reading the csv into pandas.

def csv_test_input(df_train):
    """ Function to take File based inputs for Network parameter """
    uploaded_file = st.sidebar.file_uploader("Telecom Network Test-Data", type="csv")

    if uploaded_file is None:
        return None

    text_io = io.TextIOWrapper(uploaded_file)

    inputDF = pd.read_csv(text_io)
    text_io.seek(0)

    return inputDF

Previously we were creating a new buffer for you each time we reran. To optimize, we are returning the same buffer on rerun. Unfortunately, this means that if you’ve already read the buffer, you’ll need to reset after. If you use .getValue() , there’s no need to seek . Unfortunately for file uploader pandas.read_csv does a read() which will require a buffer reset.

1 Like
3

this doesn’t solves my problem, it is still giving me the same error message.
.seek(0) will work if file is open, here the erro is saying that I/O file is closed, i.e. uploaded_file is closed.

can you suggest any workarounds ???

or alternate way to read a csv file into panda frame. I am ready to change my code as well.

Thanks in anticipation.

-Regards,
Irfan

4 
def csv_test_input(df_train):
    """ Function to take File based inputs for Network parameter """
    uploaded_file = st.sidebar.file_uploader("Telecom Network Test-Data", type="csv")
    if uploaded_file is None:
        return None

    # st.text ("File is closed ? --> {} ".format(uploaded_file.closed))
    uploaded_file.seek(0)
    inputDF = pd.read_csv(uploaded_file)
    # st.text ("File is closed ? --> {} ".format(uploaded_file.closed))
    return inputDF

Thanks @karriebear, for your suggestion,
I tried to modify my code and it worked for me .

-Regards,
Irfan

1 Like