[FIXED] Matplotlib line plot of data and projections missing a connection

Issue

I have the following dataframe:

df =pd.DataFrame( {'Area': ['Water', 'Water', 'Water', 'Water', 'Water'],
      'Year': ['2021', '2022', '2023', '2024', '2025'],
      'Amount': [1530.72, 1925.39, 1700.00, 2000.00, 2160.00],
      'Type': ['Actuals', 'Actuals', 'Actuals', 'Budget', 'Budget']})

I'd like to plot make a line plot with the Year on the X axis and the amount on the Y axis. I'd like the linetype for the 'Actuals' to be solid, and to be dotted for the 'Budget'.

I can almost do this, but I get I am missing the connection between 2023 and 2024.

plt.plot('Year', 'Amount', data=df[df['Type'] == 'Actuals'], marker='o', color='grey', linewidth=2)
plt.plot('Year', 'Amount', data=df[df['Type'] == 'Budget'], marker='o', color='grey', linewidth=2, linestyle='--')

What am I doing wrong here?

Solution

As pointed out by @Gaberocksall in the comments, you are not asking matplotlib to draw line from 2023 to 2024, which is why it doesn't exist in your plot.

You could get the result you want by expanding the Budget dataset to include the last line of the Actuals dataset:

plt.plot('Year', 
    'Amount',
    data=df[df['Type'] == 'Actuals'],
    marker='o', color='grey', linewidth=2
)
plt.plot('Year',
    'Amount',
    data=pd.concat([df[df['Type']=='Actuals'].iloc[-1:], df[df['Type'] == 'Budget']]),
    marker='o', color='grey', linewidth=2, linestyle='--'
)
plt.show()

Answered By - Nick