Add plotly[express] extra for easily installing Plotly Express dependencies

contributing.md

@@ -140,17 +140,17 @@ We will support Python 3.12 and higher versions soon.
 
 ### Install requirements - (Non-Windows)
 ```bash
-(plotly_dev) $ pip install -r packages/python/plotly/requirements.txt
-(plotly_dev) $ pip install -r packages/python/plotly/optional-requirements.txt
+(plotly_dev) $ pip install -r packages/python/plotly/requires-install.txt
+(plotly_dev) $ pip install -r packages/python/plotly/requires-dev.txt
  ```
 ### Install requirements - (Windows + Conda)
 Because Windows requires Visual Studio libraries to compile some of the optional dependencies, follow these steps to
 complete installation and avoid gdal-config errors.
 
 ```bash
-(plotly_dev) $ pip install -r packages/python/plotly/requirements.txt
+(plotly_dev) $ pip install -r packages/python/plotly/requires-install.txt
 (plotly_dev) $ conda install fiona
-(plotly_dev) $ pip install -r packages/python/plotly/optional-requirements.txt
+(plotly_dev) $ pip install -r packages/python/plotly/requires-dev.txt
 ```
 
 ### Editable install of plotly packages
@@ -173,7 +173,7 @@ documentation on _development mode_.
 This repo uses the [Black](https://black.readthedocs.io/en/stable/) code formatter,
 and the [pre-commit](https://pre-commit.com/) library to manage a git commit hook to
 run Black prior to each commit.  Both pre-commit and black are included in the
-`packages/python/plotly/optional-requirements.txt` file, so you should have them
+`packages/python/plotly/requires-dev.txt` file, so you should have them
 installed already if you've been following along.
 
 To enable the Black formatting git hook, run the following from within your virtual
@@ -261,7 +261,7 @@ We take advantage of two tools to run tests:
 
 ### Running Tests with `pytest`
 
-Since our tests cover *all* the functionality, to prevent tons of errors from showing up and having to parse through a messy output, you'll need to install `optional-requirements.txt` as explained above.
+Since our tests cover *all* the functionality, to prevent tons of errors from showing up and having to parse through a messy output, you'll need to install `requires-dev.txt` as explained above.
 
 After you've done that, go ahead and run the test suite!
 

packages/python/plotly/plotly/express/__init__.py

@@ -2,13 +2,24 @@
 `plotly.express` is a terse, consistent, high-level wrapper around `plotly.graph_objects`
 for rapid data exploration and figure generation. Learn more at https://plotly.com/python/plotly-express/
 """
+
 from plotly import optional_imports
 
 pd = optional_imports.get_module("pandas")
 if pd is None:
     raise ImportError(
         """\
-Plotly express requires pandas to be installed."""
+Plotly Express requires pandas to be installed. You can install pandas using pip with:
+
+$ pip install pandas
+
+Or install Plotly Express and its dependencies directly with:
+
+$ pip install "plotly[pandas]"
+
+You can also use Plotly Graph Objects to create a large number of charts without installing
+pandas. See examples here: https://plotly.com/python/graph-objects/
+"""
     )
 
 from ._imshow import imshow

packages/python/plotly/optional-requirements.txt → packages/python/plotly/requires-dev.txt

@@ -1,7 +1,7 @@
 ### Optional Dependencies for Additional Plotly Functionality   ###
 ###                                                             ###
 ### To install, run:                                            ###
-###      $ pip install -r optional-requirements.txt             ###
+###      $ pip install -r requires-dev.txt             ###
 ###                                                             ###
 ###################################################################
 

packages/python/plotly/requires-install.txt

@@ -0,0 +1,2 @@
+tenacity>=6.2.0
+packaging

packages/python/plotly/requires-pandas.txt

@@ -0,0 +1,2 @@
+pandas; python_version <= '3.8' # Loose requirement for older Python as older numpy is not supported
+pandas>=2.2.0; python_version > '3.0' # Minimum pin to ensure compatibility with all versions of numpy

packages/python/plotly/setup.py

@@ -65,6 +65,7 @@
 else:
     skip_npm = False
 
+
 # Load plotly.js version from js/package.json
 def plotly_js_version():
     path = os.path.join(
@@ -273,9 +274,7 @@ def overwrite_plotlyjs_version_file(plotlyjs_version):
 # DO NOT EDIT
 # This file is generated by the updatebundle setup.py command
 __plotlyjs_version__ = "{plotlyjs_version}"
-""".format(
-                plotlyjs_version=plotlyjs_version
-            )
+""".format(plotlyjs_version=plotlyjs_version)
         )
 
 
@@ -289,9 +288,7 @@ def overwrite_plotlywidget_version_file(version):
 #
 # It is edited by hand prior to official releases
 __frontend_version__ = "{version}"
-""".format(
-                version=version
-            )
+""".format(version=version)
         )
 
 
@@ -303,7 +300,6 @@ def request_json(url):
 
 
 def get_latest_publish_build_info(repo, branch):
-
     url = (
         r"https://circleci.com/api/v1.1/project/github/"
         r"{repo}/tree/{branch}?limit=100&filter=completed"
@@ -537,6 +533,14 @@ def run(self):
 ]
 
 versioneer_cmds = versioneer.get_cmdclass()
+
+
+def read_req_file(req_type):
+    with open(f"requires-{req_type}.txt", encoding="utf-8") as fp:
+        requires = (line.strip() for line in fp)
+        return [req for req in requires if req and not req.startswith("#")]
+
+
 setup(
     name="plotly",
     version=versioneer.get_version(),
@@ -603,7 +607,11 @@ def run(self):
     data_files=[
         ("etc/jupyter/nbconfig/notebook.d", ["jupyterlab-plotly.json"]),
     ],
-    install_requires=["tenacity>=6.2.0", "packaging"],
+    install_requires=read_req_file("install"),
+    extras_require={
+        "pandas": read_req_file("pandas"),
+        "dev": read_req_file("dev"),
+    },
     zip_safe=False,
     cmdclass=dict(
         build_py=js_prerelease(versioneer_cmds["build_py"]),