Adding support for pandas dataframes, multindex formatting

docs/Maths.md

@@ -109,7 +109,7 @@ Result:
 
 Create a table with pandas [DataFrame](https://pandas.pydata.org/docs/reference/api/pandas.DataFrame.html):
 ```python
-from fpdf import FPDF
+from fpdf.adapters.table_pandas import FPDF_pandas
 import pandas as pd
 
 df = pd.DataFrame(
@@ -121,25 +121,16 @@ df = pd.DataFrame(
     }
 )
 
-df = df.applymap(str)  # Convert all data inside dataframe into string type
-
-columns = [list(df)]  # Get list of dataframe columns
-rows = df.values.tolist()  # Get list of dataframe rows
-data = columns + rows  # Combine columns and rows in one list
-
-pdf = FPDF()
+pdf = FPDF_pandas()
 pdf.add_page()
 pdf.set_font("Times", size=10)
-with pdf.table(borders_layout="MINIMAL",
-               cell_fill_color=200,  # grey
-               cell_fill_mode="ROWS",
-               line_height=pdf.font_size * 2.5,
-               text_align="CENTER",
-               width=160) as table:
-    for data_row in data:
-        row = table.row()
-        for datum in data_row:
-            row.cell(datum)
+pdf.dataframe(df,
+        borders_layout="MINIMAL",
+        cell_fill_color=200,  # grey
+        cell_fill_mode="ROWS",
+        line_height=pdf.font_size * 2.5,
+        text_align="CENTER",
+        width=160)
 pdf.output("table_from_pandas.pdf")
 ```
 

docs/Tables.md

@@ -380,6 +380,8 @@ Result:
 
 ![](table_with_multiple_headings.png)
 
+This also works with index columns. Pass any integer to the `num_index_columns` argument when calling `Table()` and that many columns will be formatted according to the `index_style` argument.
+
 ## Table from pandas DataFrame
 
 _cf._ [Maths documentation page](Maths.md#using-pandas)

fpdf/adapters/table_pandas.py

@@ -0,0 +1,38 @@
+from pandas import MultiIndex
+from fpdf import FPDF
+
+
+class FPDF_pandas(FPDF):
+    def __init__(self, **kwargs):
+        super().__init__(**kwargs)
+
+    def dataframe(self, df, **kwargs):
+        with self.table(
+            num_index_columns=df.index.nlevels,
+            num_heading_rows=df.columns.nlevels,
+            **kwargs
+        ) as table:
+            TABLE_DATA = format_df(df)
+            for data_row in TABLE_DATA:
+                row = table.row()
+                for datum in data_row:
+                    row.cell(datum)
+
+
+def format_df(df, char: str = " ", convert_to_string: bool = True) -> list:
+    data = df.map(str).values.tolist()
+    if isinstance(df.columns, MultiIndex):
+        heading = [list(c) for c in zip(*df.columns)]
+    else:
+        heading = df.columns.values.reshape(1, len(df.columns)).tolist()
+
+    if isinstance(df.index, MultiIndex):
+        index = [list(c) for c in df.index]
+    else:
+        index = df.index.values.reshape(len(df), 1).tolist()
+    padding = [list(char) * df.index.nlevels] * df.columns.nlevels
+
+    output = [i + j for i, j in zip(padding + index, heading + data)]
+    if convert_to_string:
+        output = [[str(d) for d in row] for row in output]
+    return output

fpdf/table.py

@@ -9,6 +9,7 @@
 from .util import Padding
 
 DEFAULT_HEADINGS_STYLE = FontFace(emphasis="BOLD")
+DEFAULT_INDEX_STYLE = FontFace(emphasis="BOLD")
 
 
 class Table:
@@ -32,6 +33,7 @@ def __init__(
         gutter_height=0,
         gutter_width=0,
         headings_style=DEFAULT_HEADINGS_STYLE,
+        index_style=DEFAULT_INDEX_STYLE,
         line_height=None,
         markdown=False,
         text_align="JUSTIFY",
@@ -40,6 +42,7 @@ def __init__(
         padding=None,
         outer_border_width=None,
         num_heading_rows=1,
+        num_index_columns=0
     ):
         """
         Args:
@@ -58,6 +61,8 @@ def __init__(
             gutter_width (float): optional horizontal space between columns
             headings_style (fpdf.fonts.FontFace): optional, default to bold.
                 Defines the visual style of the top headings row: size, color, emphasis...
+            index_style (fpdf.fonts.FontFace): optional, default to bold.
+                Defines the visual style of the top headings row: size, color, emphasis...
             line_height (number): optional. Defines how much vertical space a line of text will occupy
             markdown (bool): optional, default to False. Enable markdown interpretation of cells textual content
             text_align (str, fpdf.enums.Align, tuple): optional, default to JUSTIFY. Control text alignment inside cells.
@@ -72,6 +77,7 @@ def __init__(
             num_heading_rows (number): optional. Sets the number of heading rows, default value is 1. If this value is not 1,
                 first_row_as_headings needs to be True if num_heading_rows>1 and False if num_heading_rows=0. For backwards compatibility,
                 first_row_as_headings is used in case num_heading_rows is 1.
+            num_index_cols (number): optional. Sets the number of index columns, default value is 0.
         """
         self._fpdf = fpdf
         self._align = align
@@ -85,12 +91,14 @@ def __init__(
         self._gutter_height = gutter_height
         self._gutter_width = gutter_width
         self._headings_style = headings_style
+        self._index_style = index_style
         self._line_height = 2 * fpdf.font_size if line_height is None else line_height
         self._markdown = markdown
         self._text_align = text_align
         self._width = fpdf.epw if width is None else width
         self._wrapmode = wrapmode
         self._num_heading_rows = num_heading_rows
+        self.num_index_columns = num_index_columns
         self._initial_style = None
         self.rows = []
 
@@ -129,13 +137,16 @@ def __init__(
             self.row(row)
 
     def row(self, cells=(), style=None):
-        "Adds a row to the table. Yields a `Row` object."
+        "Adds a row to the table. Yields a `Row` object. Styles first `self.num_index_columns` cells  with `self.index_style`"
         if self._initial_style is None:
             self._initial_style = self._fpdf.font_face()
         row = Row(self, style=style)
         self.rows.append(row)
-        for cell in cells:
-            row.cell(cell)
+        for n, cell in enumerate(cells):
+            if n < self.num_index_columns:
+                row.cell(cell, style=self._index_style)
+            else:
+                row.cell(cell)
         return row
 
     def render(self):

test/table/test_table.py

@@ -1,9 +1,11 @@
 import logging
 from pathlib import Path
+import pandas as pd
 
 import pytest
 
 from fpdf import FPDF, FPDFException
+from fpdf.adapters.table_pandas import FPDF_pandas
 from fpdf.drawing import DeviceRGB
 from fpdf.fonts import FontFace
 from test.conftest import assert_pdf_equal, LOREM_IPSUM
@@ -37,6 +39,13 @@
     ("3", "4", "5", "6", "7", "8"),
 )
 
+MULTI_LABEL_TABLE_DATA = {
+    ("tall", "fat"): {"color": "red", "number": 7, "happy": False},
+    ("short", "fat"): {"color": "green", "number": 8, "happy": True},
+    ("tall", "lean"): {"color": "blue", "number": 9, "happy": True},
+    ("short", "lean"): {"color": "yellow", "number": 15, "happy": False},
+}
+
 
 def test_table_simple(tmp_path):
     pdf = FPDF()
@@ -86,6 +95,17 @@ def test_table_with_syntactic_sugar(tmp_path):
         table.row(TABLE_DATA[4])
     assert_pdf_equal(pdf, HERE / "table_simple.pdf", tmp_path)
 
+def test_pandas_multi_label(tmp_path):
+    for df, i in zip(
+        [pd.DataFrame(MULTI_LABEL_TABLE_DATA), pd.DataFrame(MULTI_LABEL_TABLE_DATA).T],
+        ["heading", "index"],
+    ):
+        pdf = FPDF_pandas()
+        pdf.add_page()
+        pdf.set_font("Times", size=10)
+        pdf.dataframe(df, borders_layout="MINIMAL", text_align="CENTER", width=160)
+        assert_pdf_equal(pdf, HERE / f"table_pandas_multi{i}.pdf", tmp_path)
+
 
 def test_table_with_fixed_col_width(tmp_path):
     pdf = FPDF()