Python mplfinance draw hlines start/end date

Question

I have a problem. I am trying to draw hlines in my mplfinance chart. For that I have the following code:

levels = [(8531.0, Timestamp('2020-02-27 00:00:00')), (8971.77, Timestamp('2020-02-27 16:00:00')), (8799.0, Timestamp('2020-02-28 22:00:00'))]

mpf.plot(candlesticks,
            type='candle',
            style='charles',
            hlines=levels)

I am trying to draw horizontal lines on my chart. These lines are called hlines and they need to start at a specific date, so the width of the line shouldn't be the full width of the chart, but if the start date is halfway of the chart. The line should be starting in the middle of the chart through the end. Another thing that is important, is that I want to be able to draw multiple lines, so in my code I had the first line on level 8531.0 starting from 2020-02-27 00:00:00 and another line at level 8971.77 starting from 2020-02-27 16:00:00, but I get the following error:

Traceback (most recent call last):
  File "c:\Users\Alexander\Projects\MyProject\Python\run.py", line 150, in <module>
    run()
  File "c:\Users\Alexander\Projects\MyProject\Python\run.py", line 128, in run
    graph.plot()
  File "c:\Users\Alexander\Projects\MyProject\Python\graph.py", line 18, in run
    plotCandlestickData(candlesticks[intervalMedium]['candlesticks'])
  File "c:\Users\Alexander\Projects\MyProject\Python\graph.py", line 49, in plotData
    mpf.plot(candlesticks,
  File "C:\Users\Alexander\AppData\Local\Programs\Python\Python310\lib\site-packages\mplfinance\plotting.py", line 389, in plot
    config = _process_kwargs(kwargs, _valid_plot_kwargs())
  File "C:\Users\Alexander\AppData\Local\Programs\Python\Python310\lib\site-packages\mplfinance\_arg_validators.py", line 322, in _process_kwargs
    raise TypeError('kwarg "'+key+'" validator returned False for value: "'+str(value)+'"\n    '+v)
TypeError: kwarg "hlines" validator returned False for value: "[(8531.0, Timestamp('2020-02-27 00:00:00')), (8971.77, Timestamp('2020-02-27 16:00:00')), (8799.0, Timestamp('2020-02-28 22:00:00'))]"
    'Validator'   : lambda value: _hlines_validator(value) },

Why am I getting this error? First I thought I should provide another timestamp as endtime, but that resulted in the same error.

When I remove the timestamp from the values, I get a graph like this:

But those lines you see are all full width, which is not what I want. I want each line to start on a given timestamp. How can I achieve this?

Answer 1

In addition to vertical and horizontal lines, sloping lines can also be drawn. The settings for such lines can be set in alines in the form of a tuple list. See the official example.

import mplfinance as mpf
import yfinance as yf

candlesticks = yf.download("AAPL", start="2022-01-01", end="2022-04-01")

#levels = [155,160,180]
levels = [[('2022-02-16', 160.), ('2022-03-31',160.0)], [('2022-02-16',175.0),('2022-03-31',175.0)]]

mpf.plot(candlesticks,
         type='candle',
         style='charles',
         alines=dict(alines=levels, colors=['r','b'])
            )