Add rows to the datatable-Error loading dependencies - plotly-dash

Question

I want to create an app that a user can upload CSV files and it will show a data table that the user can edit, add columns and add rows. There are also two dropdowns that contain the value of the columns of the data table. But I get Error loading dependencies after I run the code. Can anyone teach me how to fix this error?
Below is the code:
import base64
import io
import dash
from dash.dependencies import Input, Output, State
import dash_core_components as dcc
import dash_html_components as html
import dash_table
import pandas as pd
from dash.exceptions import PreventUpdate
external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']
app = dash.Dash(__name__, external_stylesheets=external_stylesheets)
app.config.suppress_callback_exceptions = True
app.layout = html.Div([
dcc.Upload(
id='datatable-upload',
children=html.Div([
'Drag and Drop or ',
html.A('Select Files')
]),
style={
'width': '100%', 'height': '60px', 'lineHeight': '60px',
'borderWidth': '1px', 'borderStyle': 'dashed',
'borderRadius': '5px', 'textAlign': 'center', 'margin': '10px'
},
),
html.Div([
dcc.Input(
id='adding-rows-name',
placeholder='Enter a column name...',
value='',
style={'padding': 10}
),
html.Button('Add Column', id='adding-rows-button', n_clicks=0)
], style={'height': 50}),
html.Div(id='output-data-upload'),
html.Button('Add Row', id='editing-rows-button', n_clicks=0),
dcc.Dropdown(
id='data_selector1',
options=[
{'label': '', 'value': ''}
],
value=[]
),
dcc.Dropdown(
id='data_selector2',
options=[
{'label': '', 'value': ''}
],
value=[]
),
])
def parse_contents(contents, filename):
content_type, content_string = contents.split(',')
decoded = base64.b64decode(content_string)
if 'csv' in filename:
# Assume that the user uploaded a CSV file
return pd.read_csv(
io.StringIO(decoded.decode('utf-8')))
elif 'xls' in filename:
# Assume that the user uploaded an excel file
return pd.read_excel(io.BytesIO(decoded))
#app.callback(Output('output-data-upload', 'children'),
[Input('datatable-upload', 'contents')],
[State('datatable-upload', 'filename')])
def update_output(contents, filename):
if contents is None:
return []
df = parse_contents(contents, filename)
return html.Div([
dash_table.DataTable(
id='table',
style_data={
'whiteSpace': 'normal',
'height': 'auto'
},
style_table={'overflowX': 'scroll',
'maxHeight': '300',
'overflowY': 'scroll'},
style_cell={
'minWidth': '150px', 'maxWidth': '180px',
'whiteSpace': 'normal',
'textAlign': 'left'
},
style_header={
'fontWeight': 'bold',
},
fixed_rows={ 'headers': True, 'data': 0 },
columns=[{"name": i, "id": i, 'deletable': True, 'renamable': True} for i in df.columns],
data=df.to_dict("records"),
row_deletable=True,
filter_action="native",
sort_action="native",
sort_mode='multi',
editable=True,
)
])
#The code will work if I remove this function
#app.callback(
Output('table', 'data'),
[Input('editing-rows-button', 'n_clicks')],
[State('table', 'data'),
State('table', 'columns')])
def add_row(n_clicks, rows, columns):
if n_clicks > 0:
rows.append({i['id']: '' for i in columns})
return rows
#app.callback(
Output('table', 'columns'),
[Input('adding-rows-button', 'n_clicks')],
[State('adding-rows-name', 'value'),
State('table', 'columns')])
def update_columns(n_clicks, value, existing_columns):
if n_clicks > 0:
existing_columns.append({
'id': value, 'name': value,
'renamable': True, 'deletable': True
})
return existing_columns
#app.callback(Output('data_selector1', 'options'),
[Input('table', 'data')])
def update_dropdown(rows):
if rows is None:
raise PreventUpdate
df = pd.DataFrame(rows)
print('updating menus')
columns = df.columns
col_labels = [{'label': k, 'value': k} for k in columns]
return col_labels
#app.callback(Output('data_selector2', 'options'),
[Input('table', 'data')])
def update_dropdown2(rows):
if rows is None:
raise PreventUpdate
df = pd.DataFrame(rows)
print('updating menus')
columns = df.columns
col_labels = [{'label': k, 'value': k} for k in columns]
return col_labels
if __name__ == '__main__':
app.run_server(debug=False)
The code will work if I remove the add rows to the data table function.