Update this melt so that it is not mandatory to have a 'time' indice

[fredmontet]

ontime/src/ontime/core/plotting/plot.py

Line 57 in ec442e3

df = df.melt("time", var_name="variable", value_name="value")

[fredmontet]

Here you go @ben-jy, I added everything in the param of the function to be able to adjust this when needed, while staying non-destructive.

[ben-jy]

there is another problem that could be fix in this issue. When a time series has a component named "value", an error is raised :

ts = on.TimeSeries.from_darts(EnergyDataset().load())[:1000]
ts.rename({"generation biomass": "value"}).plot()

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
Cell In[39], line 1
----> 1 ts.rename({"generation biomass": "value"}).plot()

File ~/projects_dev/ontime/docs/../src/ontime/core/time_series/time_series.py:32, in TimeSeries.plot(self, width, height, **kwargs)
     28 from ..plotting.plot import Plot
     29 from ..plotting._marks.line import line
     31 return (
---> 32     Plot(self).add(line, **kwargs).properties(width=width, height=height).show()
     33 )

File ~/projects_dev/ontime/docs/../src/ontime/core/plotting/plot.py:26, in Plot.add(self, mark, ts, **kwargs)
     17 """
     18 Add a mark to the plot
     19 
   (...)
     23 :return: Plot
     24 """
     25 ts = self.ts if ts is None else ts
---> 26 self.layers.append(mark(ts, **kwargs))
     27 return self

File ~/projects_dev/ontime/docs/../src/ontime/core/plotting/_marks/line.py:17, in line(ts, type, encode_kwargs)
      7 def line(ts: TimeSeries, type: str = None, encode_kwargs: dict = None) -> Chart:
      8     """
      9     Line plot for TimeSeries
     10 
   (...)
     14     :return: Altair Chart
     15     """
---> 17     df = Plot.melt(ts)
     19     default_kwargs = {
     20         "x": "time:T",
     21         "y": "value:Q",
     22         "color": "variable:N",
     23     }
     24     encode_kwargs = encode_kwargs if encode_kwargs is not None else default_kwargs

File ~/projects_dev/ontime/docs/../src/ontime/core/plotting/plot.py:57, in Plot.melt(ts)
     55 df = ts.pd_dataframe()
     56 df = df.reset_index()
---> 57 df = df.melt("time", var_name="variable", value_name="value")
     58 return df

File ~/.cache/pypoetry/virtualenvs/ontime-2OQVvbNf-py3.10/lib/python3.10/site-packages/pandas/core/frame.py:9942, in DataFrame.melt(self, id_vars, value_vars, var_name, value_name, col_level, ignore_index)
   9932 @Appender(_shared_docs["melt"] % {"caller": "df.melt(", "other": "melt"})
   9933 def melt(
   9934     self,
   (...)
   9940     ignore_index: bool = True,
   9941 ) -> DataFrame:
-> 9942     return melt(
   9943         self,
   9944         id_vars=id_vars,
   9945         value_vars=value_vars,
   9946         var_name=var_name,
   9947         value_name=value_name,
   9948         col_level=col_level,
   9949         ignore_index=ignore_index,
   9950     ).__finalize__(self, method="melt")

File ~/.cache/pypoetry/virtualenvs/ontime-2OQVvbNf-py3.10/lib/python3.10/site-packages/pandas/core/reshape/melt.py:54, in melt(frame, id_vars, value_vars, var_name, value_name, col_level, ignore_index)
     43 @Appender(_shared_docs["melt"] % {"caller": "pd.melt(df, ", "other": "DataFrame.melt"})
     44 def melt(
     45     frame: DataFrame,
   (...)
     51     ignore_index: bool = True,
     52 ) -> DataFrame:
     53     if value_name in frame.columns:
---> 54         raise ValueError(
     55             f"value_name ({value_name}) cannot match an element in "
     56             "the DataFrame columns."
     57         )
     58     id_vars = ensure_list_vars(id_vars, "id_vars", frame.columns)
     59     value_vars_was_not_none = value_vars is not None

ValueError: value_name (value) cannot match an element in the DataFrame columns.

[ben-jy]

Here you go @ben-jy, I added everything in the param of the function to be able to adjust this when needed, while staying non-destructive.

Actually, melt() method is never called directly by the user, the parameters to define the time index and value column names should be given at the time the plot is created (i guess)