我是新来的 Plotly Dash框架并尝试构建一个简单的仪表板:
2a.如果未选择 CSV 文件(和结果数据框)，则不呈现任何内容。
我的 CSV 文件中的数据类似于以下内容:
df = pd.DataFrame({'Make':['Ford', 'Ford', 'Ford', 'BMW', 'BMW', 'BMW', Mercedes', 'Mercedes', 'Mercedes'],
'Score':['88.6', '76.6', '100', '79.1', '86.8', '96.4', '97.3', '98.7', '98.5'],
'Dimension':['Speed', 'MPG', 'Styling', 'Speed', 'MPG', 'Styling', 'Speed', 'MPG', 'Styling'],
'Month':['Apr-19', 'Apr-19', 'Apr-19', 'Apr-19', 'Apr-19', 'Apr-19', 'Apr-19', 'Apr-19', 'Apr-19']})
我的代码如下:
import base64
import datetime
import io
import dash
from dash.dependencies import Input, Output, State
import dash_core_components as dcc
import dash_html_components as html
import plotly.graph_objects as go
import dash_table
import pandas as pd
app = dash.Dash()
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)
try:
if 'csv' in filename:
# Assume that the user uploaded a CSV file
df = pd.read_csv(
io.StringIO(decoded.decode('utf-8')))
elif 'xls' in filename:
# Assume that the user uploaded an excel file
df = pd.read_excel(io.BytesIO(decoded))
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)),
dash_table.DataTable(
data=df.to_dict('records'),
columns=[{'name': i, 'id': i} for i in df.columns]
),
html.Hr(), # horizontal line
#### How to get the x and y values DYNAMICALLY from the data frame to pass into the Bar() function? ####
dcc.Graph(
figure = go.Figure(data=[
go.Bar(name=df.columns.values[0], x=pd.unique(df['Make']), y=[88.6, 76.6, 100], text=[88.6, 76.6, 100], textposition='auto'),
go.Bar(name=df.columns.values[1], x=pd.unique(df['Make']), y=[92.5, 93.6, 93.4], text=[92.5, 93.6, 93.4], textposition='auto'),
go.Bar(name=df.columns.values[2], x=pd.unique(df['Make']), y=[99.1, 99.2, 95.9], text=[99.1, 99.2, 95.9], textposition='auto'),
])
),
html.Hr(),
# For debugging, display the raw contents provided by the web browser
html.Div('Raw Content'),
html.Pre(contents[0:200] + '...', style={
'whiteSpace': 'pre-wrap',
'wordBreak': 'break-all'
})
])
@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)
我可以上传和查看 CSV 文件的内容。
然而，
go.Bar()函数有它的x和 y值“硬编码”。它们不一定是动态的(即如果 x 变量的数量发生变化等)。 如何让 Dash 根据使用
parse_contents(contents, filename, date) 上传的 CSV 文件中的数据构建条形图功能？我试图在 Using dash upload component to upload csv file and generate a graph 中跟进，但无法成功实现该示例。
在此先感谢您帮助新手使这个玩具示例正常工作!
最佳答案
这是答案:
import base64
import datetime
import io
import dash
from dash.dependencies import Input, Output, State
import dash_core_components as dcc
import dash_html_components as html
import plotly.express as px
import plotly.graph_objects as go
import dash_table
import pandas as pd
app = dash.Dash()
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)
try:
if 'csv' in filename:
# Assume that the user uploaded a CSV file
df = pd.read_csv(
io.StringIO(decoded.decode('utf-8')))
elif 'xls' in filename:
# Assume that the user uploaded an excel file
df = pd.read_excel(io.BytesIO(decoded))
except Exception as e:
print(e)
return html.Div([
'There was an error processing this file.'
])
return html.Div([
dcc.Graph(
figure = go.Figure(data=[
go.Bar(name=df.columns.values[0], x=pd.unique(df['Make']), y=df['Score'], text=df['Score'], textposition='auto'),
])
),
])
@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)
关于python - 将 CSV 上传到 Plotly Dash 并基于 Pandas 数据框渲染条形图，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/62097062/