Matplotlib Fill_Between 两行

Question

Good Morning, I'm Trying to use Matplotlib to Fill_between two Lines and i'm doing like this:

plt.figure(figsize = (16,8));
plt.plot(estudo_df["Sales"], label='Original Data');
plt.plot(forecast_2018["yhat"], color='red', label='Predictions');
plt.plot(forecast_2018["yhat_lower"], color='green', label='Predictions Lower');
plt.plot(forecast_2018["yhat_upper"], color='Blue', label='Predictions Blue');
plt.fill_between(forecast_2018["yhat_lower"],forecast_2018["yhat_upper"] , color='grey', alpha='0.5')
plt.legend();
plt.title('Forecast Sales Prophet - '+sh);
plt.xlabel('Date');
plt.ylabel('Sales');

But it is not working...

I use two DS that have the same amount and "index ID", which is a DATE, estudo_df and forecast_2018

Does anyone knows where the error is?

Answer 1

Change your code in 2 places:

• pass forecast_2018.index as the first parameter of fill_between ,
• change alpha parameter to float (you passed a string ).

I ran your code with one line commented out:

plt.figure(figsize = (8, 6));
#plt.plot(estudo_df["Sales"], label='Original Data');
plt.plot(forecast_2018["yhat"], color='red', label='Predictions');
plt.plot(forecast_2018["yhat_lower"], color='green', label='Predictions Lower');
plt.plot(forecast_2018["yhat_upper"], color='blue', label='Predictions Blue');
plt.fill_between(forecast_2018.index, forecast_2018["yhat_lower"],
    forecast_2018["yhat_upper"], color='#DDDDDD', alpha=0.5)
plt.legend();
sh = 'xx'
plt.title('Forecast Sales Prophet - ' + sh)
plt.xlabel('Date')
plt.ylabel('Sales');

and got:

The index of my DataFrame contains dates but is of string type.