Display a file uploader widget.

By default, uploaded files are limited to 200MB. You can configure this using the server.maxUploadSize config option. For more info on how to set config options, see https://docs.streamlit.io/library/advanced-features/configuration#set-configuration-options

Function signature

st.file_uploader(label, type=None, accept_multiple_files=False, key=None, help=None, on_change=None, args=None, kwargs=None, *, disabled=False, label_visibility="visible")

Parameters

label (str)

A short label explaining to the user what this file uploader is for. For accessibility reasons, you should never set an empty label (label="") but hide it with label_visibility if needed. In the future, we may disallow empty labels by raising an exception.

type (str or list of str or None)

Array of allowed extensions. ['png', 'jpg'] The default is None, which means all extensions are allowed.

accept_multiple_files (bool)

If True, allows the user to upload multiple files at the same time, in which case the return value will be a list of files. Default: False

key (str or int)

An optional string or integer to use as the unique key for the widget. If this is omitted, a key will be generated for the widget based on its content. Multiple widgets of the same type may not share the same key.

help (str)

A tooltip that gets displayed next to the file uploader.

on_change (callable)

An optional callback invoked when this file_uploader's value changes.

args (tuple)

An optional tuple of args to pass to the callback.

kwargs (dict)

An optional dict of kwargs to pass to the callback.

disabled (bool)

An optional boolean, which disables the file uploader if set to True. The default is False. This argument can only be supplied by keyword.

label_visibility ("visible" or "hidden" or "collapsed")

The visibility of the label. If "hidden", the label doesn’t show but there is still empty space for it above the widget (equivalent to label=""). If "collapsed", both the label and the space are removed. Default is "visible". This argument can only be supplied by keyword.

Returns

(None or UploadedFile or list of UploadedFile)

  • If accept_multiple_files is False, returns either None or an UploadedFile object.
  • If accept_multiple_files is True, returns a list with the uploaded files as UploadedFile objects. If no files were uploaded, returns an empty list.

The UploadedFile class is a subclass of BytesIO, and therefore it is "file-like". This means you can pass them anywhere where a file is expected.

Examples

Insert a file uploader that accepts a single file at a time:

uploaded_file = st.file_uploader("Choose a file")
if uploaded_file is not None:
    # To read file as bytes:
    bytes_data = uploaded_file.getvalue()
    st.write(bytes_data)

    # To convert to a string based IO:
    stringio = StringIO(uploaded_file.getvalue().decode("utf-8"))
    st.write(stringio)

    # To read file as string:
    string_data = stringio.read()
    st.write(string_data)

    # Can be used wherever a "file-like" object is accepted:
    dataframe = pd.read_csv(uploaded_file)
    st.write(dataframe)

Insert a file uploader that accepts multiple files at a time:

uploaded_files = st.file_uploader("Choose a CSV file", accept_multiple_files=True)
for uploaded_file in uploaded_files:
    bytes_data = uploaded_file.read()
    st.write("filename:", uploaded_file.name)
    st.write(bytes_data)
(view standalone Streamlit app)

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