Remove bars with 0 height in a bar graph in dash - python-3.x

Question

I am trying to make a group bar graph in dash, I am plotting subject codes on the x-axis so they are not continuous numbers and I am getting empty bars for the missing subject codes so is there any way to remove these spaces or invisible bars.
This is the bar graph I am getting.
This is my code.
df = pd.read_csv('sampledata.csv')
a=df['SiteCode'].loc[df['SubjectStatus']=='In Progress'].value_counts()
a.index=a.index.astype(str)
b=df['SiteCode'].loc[df['SubjectStatus']=='Withdrawn'].value_counts()
b.index=b.index.astype(str)
x1=a.index
x2=b.index
trace1=go.Bar(
x=x1,
y=a.values,
name='In Progress',
)
trace2=go.Bar(
x=x2,
y=b.values,
name='Withdrawn',
)
app = dash.Dash()
app.layout = html.Div(
dcc.Graph(id='graph',
figure=go.Figure(data=[trace1,trace2],layout=go.Layout(barmode='group')))
if __name__=='__main__':
app.run_server()
Thanks in advance
PS: I am a noob in dash and python both so go easy on me.

Answer 1

You should try set barmode='stack', because barmode='group' added empty space if your one of your traces have empty values.
import dash
from dash.dependencies import Output, Input
import dash_core_components as dcc
import dash_html_components as html
import plotly
import plotly.graph_objs as go
import pandas as pd
app = dash.Dash(__name__)
df = pd.DataFrame({'x': [100, 100, 105, 110, 110, 115, 120, 125],
'y': [1, 2, 1, 1, 2, 2, 1, 1]})
colors = {
'background': '#111111',
'background2': '#FF0',
'text': '#7FDBFF'
}
df1 = df.loc[df["y"] == 1]
df2 = df.loc[df["y"] == 2]
trace1 = go.Bar(
x=df1["x"],
y=df1["y"],
name='In Progress',
)
trace2 = go.Bar(
x=df2["x"],
y=df2["y"],
name='Withdrawn',
)
app.layout = html.Div(children=[
html.Div([
html.H5('ANNx'),
dcc.Graph(
id='cx1',
figure=go.Figure(data=[trace1, trace2],
layout=go.Layout(barmode='group')))],)])
if __name__ == '__main__':
app.run_server(debug=True)
For example, in this code at value 105, 115 and 120 one trace is empty and this create space in plot:
Using another barmode solved this problem: