I’ve run into some strange behavior (or at least what I think is strange behavior)when using the Dash library and I apologies in advance as I don’t think I can’t make an example which is easy to reproduce, so instead I will include all the information I think is relevant.
I was trying to create a small dashboard which loaded some data and then plotted it in a bar chart. The code I used for this is below (it is adapted from the Docs):
import dash import dash_core_components as dcc import dash_html_components as html import plotly.express as px import pandas as pd import os.path as path def find_unique_id(data, first_name, second_name, season): name = first_name + '_' + second_name data_filt = data[data['season'] == season] data_filt = data_filt[data_filt['name'] == name] print(data_filt['unique_id']) return data_filt['unique_id'].iloc external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css'] app = dash.Dash(__name__, external_stylesheets=external_stylesheets) # assume you have a "long-form" data frame # see https://plotly.com/python/px-arguments/ for more options path_data = path.join(path.dirname(path.dirname(path.abspath(__file__))), 'Processed', 'player_database.csv') data = pd.read_csv(path_data) unique_id =  unique_id.append(find_unique_id(data, 'Harry', 'Kane', 2020)) unique_id.append(find_unique_id(data, 'Mohamed', 'Salah', 2020)) unique_id.append(find_unique_id(data, 'Heung-Min', 'Son', 2020)) fig = px.bar(data[data['unique_id'].isin(unique_id)], x="round", y="points_mean3", color="name", barmode="group") app.layout = html.Div(children=[ html.H1(children='Hello Dash'), html.Div(children=''' Dash: A web application framework for Python. '''), dcc.Graph( id='example-graph', figure=fig ) ]) if __name__ == '__main__': app.run_server(debug=True)
The player_database.csv is loaded and detailed in the picture (notice the file sizes):
However now whenever I import any Dash related module even in a different file and with nothing other than import statements (this behavior also occurs by opening a python prompt from the command line and just importing dash), it changes all the files in this folder, and appears to role them back to an earlier state. For example when I run the following code, you can see the change in file size happening:
import dash import dash_core_components as dcc import dash_html_components as html import plotly.express as px
This alters all the files in this directory (again as shown by the file size):
Does anyone know why this might be happening, has Dash got some kind of cache somewhere which loads the files it was working with from some previous state? I’ve tried googling and can’t find anything on this.
I’ve also posted this on stack overflow but thought here might be more fitting. Hope that’s OK.