plotly_express integration (#1613)

* Integrate plotly_express as plotly.express
* Remove namespace package path extension
* Remove doc references to ExpressFigure
* move legacy plotly/colors.py to plotly/colors/__init__.py

Author: jonmmease

packages/python/plotly/plotly/__init__.py

@@ -27,17 +27,15 @@
 """
 from __future__ import absolute_import
 
-# https://packaging.python.org/guides/packaging-namespace-packages/
-#         pkgutil-style-namespace-packages
-__path__ = __import__('pkgutil').extend_path(__path__, __name__)
-
 from plotly import (
     graph_objs,
     tools,
     utils,
     offline,
     colors,
     io,
+    data,
+    colors,
     _docstring_gen
 )
 

packages/python/plotly/plotly/colors.py renamed to packages/python/plotly/plotly/colors/__init__.py

@@ -81,6 +81,21 @@
 
 from plotly import exceptions
 
+
+# Built-in qualitative color sequences and sequential,
+# diverging and cyclical color scales.
+#
+# Initially ported over from plotly_express
+from . import (  # noqa: F401
+    qualitative,
+    sequential,
+    diverging,
+    cyclical,
+    cmocean,
+    colorbrewer,
+    carto,
+)
+
 DEFAULT_PLOTLY_COLORS = ['rgb(31, 119, 180)', 'rgb(255, 127, 14)',
                          'rgb(44, 160, 44)', 'rgb(214, 39, 40)',
                          'rgb(148, 103, 189)', 'rgb(140, 86, 75)',

packages/python/plotly/plotly/colors/_swatches.py

@@ -0,0 +1,37 @@
+def _swatches(module_names, module_contents):
+    """
+    Returns:
+        A `Figure` object. This figure demonstrates the color scales and
+        sequences in this module, as stacked bar charts.
+    """
+    import plotly.graph_objs as go
+
+    sequences = [
+        (k, v)
+        for k, v in module_contents.items()
+        if not (k.startswith("_") or k == "swatches")
+    ]
+
+    return go.Figure(
+        data=[
+            go.Bar(
+                orientation="h",
+                y=[name] * len(colors),
+                x=[1] * len(colors),
+                customdata=list(range(len(colors))),
+                marker=dict(color=colors),
+                hovertemplate="%{y}[%{customdata}] = %{marker.color}<extra></extra>",
+            )
+            for name, colors in reversed(sequences)
+        ],
+        layout=dict(
+            title=module_names,
+            barmode="stack",
+            barnorm="fraction",
+            template="plotly",
+            bargap=0.5,
+            showlegend=False,
+            xaxis=dict(range=[-0.02, 1.02], showticklabels=False, showgrid=False),
+            height=max(600, 40 * len(sequences)),
+        ),
+    )