ValueError with Specs parameter for subplots

📊 Plotly Python
1

Hi All,

I am creating subplots where in I need secondary y axis for the plot in 2nd row. Both plots are in same column.

I am getting the below ValueError:

ValueError:
The ‘specs’ argument to make_subplots must be a 2D list of dictionaries with dimensions (2 x 1).
Received value of type <class ‘list’>: [[{‘secondary_y’: True}, {‘secondary_y’: True}], [{‘colspan’: 1}, None]]

I believe that I am making some mistake in below line but not able to identify the mistake.

fig = make_subplots(rows=2, cols=1, print_grid=True,
                    specs=[[{"secondary_y": True}, {"secondary_y": True}], 
                           [{"colspan": 1}, None]])

Below is the complete set of the code:

import talib as ta
import yfinance as yf
import pandas as pd


import plotly.io as pio
pio.renderers.default='browser'
import plotly.graph_objects as go
from plotly.subplots import make_subplots

'''
Extracting the data
'''

VIP = yf.Ticker('VIPIND.NS')
df = VIP.history(period="max")
df.reset_index(inplace = True)
df['Date'] = pd.to_datetime(df['Date'])

'''
Creating the technical indicators
'''
df['EMA_Close'] = ta.EMA(df.Close,100)
df['MA_Close']  = ta.MA(df.Close,60)

df['MACD'],df['MACDsig'],df['MACDhist']=ta.MACD(df.Close,30,60,15)

'''
###############################
Creating Plots
###############################
'''

'''
Declaring subplots
'''
fig = make_subplots(rows=2, cols=1, print_grid=True,
                    specs=[[{"secondary_y": True}, {"secondary_y": True}], 
                           [{"colspan": 1}, None]])



'''
Plotting the first row with OHLC, EMA and MA lines
'''
fig.add_trace(go.Candlestick(x=df["Date"], open=df["Open"], high=df["High"],
                low=df["Low"], close=df["Close"], name="OHLC",showlegend=True),
                row=1, col=1,secondary_y=False)

fig.add_trace(go.Scatter(x=df['Date'], y=df['EMA_Close'], showlegend=True,
                         name="EMA Close",line=dict(color="firebrick")
                        ), row=1, col=1,secondary_y=False)

fig.add_trace(go.Scatter(x=df['Date'], y=df['MA_Close'], showlegend=True,
                         name="MA Close",line=dict(color="cornflowerblue")
                        ), row=1, col=1,secondary_y=False)


fig.add_trace(go.Scatter(x=df['Date'], y=df['MACDsig'], showlegend=True,
                         name="MACD Signal",line=dict(color="chocolate")
                        ), row=2, col=1,secondary_y=True)

fig.add_trace(go.Scatter(x=df['Date'], y=df['MACD'], showlegend=True,
                         name="MACD",line=dict(color="chartreuse")
                        ), row=2, col=1,secondary_y=True)


fig.update(layout_xaxis_rangeslider_visible=False)

fig.update_layout(height=600, width=1100)

fig.update_layout(
    title='OHLC and Volume',
    yaxis_title='Prices (Rs)',
    xaxis_title='Dates',
    yaxis_tickformat='D')

fig.update_layout(template="plotly_white")

fig.update_layout(
    margin=dict(l=20, r=20, t=40,b=20),)

# Providing desired Fonts for the plots
fig.update_layout(
    font_family="Courier New",
    font_color="blue",
    title_font_family="Times New Roman",
    title_font_color="red",
    legend_title_font_color="green")

fig.update_layout(legend=dict(
    orientation="h",
    yanchor="bottom",
    y=1.02,
    xanchor="right",
    x=1
))

fig.show()

Requesting guidance in identifying the mistake I am making to resolve this error.

Regards
Sudhir

2

It’s been two years since this question came up, but I haven’t found a comprehensive answer yet.

I believe, that the specs parameter must be a list of lists, where each inner list corresponds to a row, and should contain as many dictionaries as there are columns. In your case, this translates to:

fig = make_subplots(rows=2, cols=1, print_grid=True,
                    specs=[[{"secondary_y": True}], 
                           [{"secondary_y": True}])