Hi.
This is an example of how to parse data from a csv file using a dcc.Upload component and not pandas reader. This is in case you need to read data from multiple headers.
Example csv:
id:2020-code
filename:test.csv
Time-UTC:09:36:27
Date:05-14-20
Time, Col 1, Col 2, Col 3, Col 4
0.0000, 6.04649, 1.69522, 0.0321367, 14.7099
0.0005, 6.09178, 1.69522, 0.0321367, 14.7895
0.0010, 6.13707, 1.71105, 0.0321367, 14.7895
...
import base64
import datetime
import io
import codecs
import json
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
class CSV_FILE():
def __init__(self):
self.id = ''
self.filename = ''
self.time = ''
self.date = ''
self.df = pd.DataFrame()
def __str__(self):
return str(self.__class__) + ": " + str(self.__dict__)
external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']
app = dash.Dash(__name__, external_stylesheets=external_stylesheets)
app.layout = html.Div([
dcc.Upload(
id='upload-data',
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'
},
# Allow multiple files to be uploaded
multiple=True
),
html.Div(id='output-data-upload'),
])
def parse_contents(contents, filename, date):
content_type, content_string = contents.split(',')
decoded = base64.b64decode(content_string)
input_file = CSV_FILE()
try:
if 'csv' in filename:
# Assume that the user uploaded a CSV file
bio = io.BytesIO(decoded)
StreamReader = codecs.getreader('utf-8') # here you pass the encoding
wrapper_file = StreamReader(bio)
for number,row in enumerate(wrapper_file,start=0):
row = row.rstrip()
if number == 0:
input_file.id = row
elif number == 1:
input_file.filename = row
elif number == 2:
input_file.time = row
elif number == 3:
input_file.date = row
else:
break
input_file.df = pd.read_csv(io.StringIO(decoded.decode('utf-8')),header=4)
print(input_file)
except Exception as e:
print(e)
return html.Div([
'There was an error processing this file.'
])
return html.Div([
html.H5(filename),
html.H6(datetime.datetime.fromtimestamp(date)),
html.H6(
"Header"
),
html.Div(
input_file.id
),
html.Div(
input_file.filename
),
html.Div(
input_file.time
),
html.Div(
input_file.date
),
dash_table.DataTable(
data=input_file.df.to_dict('records'),
columns=[{'name': i, 'id': i} for i in input_file.df.columns]
),
])
@app.callback(Output('output-data-upload', 'children'),
[Input('upload-data', 'contents')],
[State('upload-data', 'filename'),
State('upload-data', 'last_modified')])
def update_output(list_of_contents, list_of_names, list_of_dates):
if list_of_contents is not None:
children = [parse_contents(c, n, d) for c, n, d in
zip(list_of_contents, list_of_names, list_of_dates)]
return children
if __name__ == '__main__':
app.run_server(debug=True)
Example:
