Html repr (pydata#3425)

* add CSS style and internal functions for html repr

* move CSS code to its own file in a new static directory

* add repr of array objects + some refactoring and fixes

* add _repr_html_ methods to dataset, dataarray and variable

* fix encoding issue in read CSS

* fix some CSS for compatibility with notebook (tested 5.2)

* use CSS grid + add icons to show/hide attrs and data repr

* Changing title of icons to make tooltips better

* Adding option to set repr back to classic

* Adding support for multiindexes

* Getting rid of some spans and fixing alignment

* Forgot to check in css [skip ci]

* Overflow on hover

* Cleaning up css

* Fixing indentation

* Replacing + icon with db icon

* Unifying input css

* Renaming stylesheet [skip ci]

* Improving styling of attributes

* Using the repr functions

* Using dask array _repr_html_

* Fixing alignment of Dimensions

* Make sure to include subdirs in package

* Adding static to manifest

* Trying to include css files

* Fixing css discrepancies in colab

* Adding in lots of escapes and also f-strings

* Adding some tests for formatting_html

* linting

* classic -> text

* linting more

* Adding tests for new option

* Trying to get better coverage

* reformatting

* Fixing up test

* Last tests hopefully

* Fixing dask test to work with lower version

* More black

* Added what's new section

* classic -> text

Co-Authored-By: Deepak Cherian <[email protected]>

* Fixing up dt/dl for jlab

* Directly change dl objects for attrs section

MANIFEST.in

@@ -6,3 +6,4 @@ prune doc/generated
 global-exclude .DS_Store
 include versioneer.py
 include xarray/_version.py
+recursive-include xarray/static *

doc/whats-new.rst

@@ -36,6 +36,12 @@ New Features
     ``pip install git+https://github.com/andrewgsavage/pint.git@refs/pull/6/head)``.
     Even with it, interaction with non-numpy array libraries, e.g. dask or sparse, is broken.
 
+- Added new :py:meth:`Dataset._repr_html_` and :py:meth:`DataArray._repr_html_` to improve
+  representation of objects in jupyter. By default this feature is turned off
+  for now. Enable it with :py:meth:`xarray.set_options(display_style="html")`.
+  (:pull:`3425`) by `Benoit Bovy <https://github.com/benbovy>`_ and
+  `Julia Signell <https://github.com/jsignell>`_.
+
 Bug fixes
 ~~~~~~~~~
 - Fix regression introduced in v0.14.0 that would cause a crash if dask is installed

setup.py

@@ -104,5 +104,7 @@
     tests_require=TESTS_REQUIRE,
     url=URL,
     packages=find_packages(),
-    package_data={"xarray": ["py.typed", "tests/data/*"]},
+    package_data={
+        "xarray": ["py.typed", "tests/data/*", "static/css/*", "static/html/*"]
+    },
 )

xarray/core/common.py

@@ -1,5 +1,6 @@
 import warnings
 from contextlib import suppress
+from html import escape
 from textwrap import dedent
 from typing import (
     Any,
@@ -18,10 +19,10 @@
 import numpy as np
 import pandas as pd
 
-from . import dtypes, duck_array_ops, formatting, ops
+from . import dtypes, duck_array_ops, formatting, formatting_html, ops
 from .arithmetic import SupportsArithmetic
 from .npcompat import DTypeLike
-from .options import _get_keep_attrs
+from .options import OPTIONS, _get_keep_attrs
 from .pycompat import dask_array_type
 from .rolling_exp import RollingExp
 from .utils import Frozen, ReprObject, either_dict_or_kwargs
@@ -134,6 +135,11 @@ def __array__(self: Any, dtype: DTypeLike = None) -> np.ndarray:
     def __repr__(self) -> str:
         return formatting.array_repr(self)
 
+    def _repr_html_(self):
+        if OPTIONS["display_style"] == "text":
+            return f"<pre>{escape(repr(self))}</pre>"
+        return formatting_html.array_repr(self)
+
     def _iter(self: Any) -> Iterator[Any]:
         for n in range(len(self)):
             yield self[n]

xarray/core/dataset.py

@@ -3,6 +3,7 @@
 import sys
 import warnings
 from collections import defaultdict
+from html import escape
 from numbers import Number
 from pathlib import Path
 from typing import (
@@ -39,6 +40,7 @@
     dtypes,
     duck_array_ops,
     formatting,
+    formatting_html,
     groupby,
     ops,
     resample,
@@ -1619,6 +1621,11 @@ def to_zarr(
     def __repr__(self) -> str:
         return formatting.dataset_repr(self)
 
+    def _repr_html_(self):
+        if OPTIONS["display_style"] == "text":
+            return f"<pre>{escape(repr(self))}</pre>"
+        return formatting_html.dataset_repr(self)
+
     def info(self, buf=None) -> None:
         """
         Concise summary of a Dataset variables and attributes.

xarray/core/formatting_html.py

@@ -0,0 +1,274 @@
+import uuid
+import pkg_resources
+from collections import OrderedDict
+from functools import partial
+from html import escape
+
+from .formatting import inline_variable_array_repr, short_data_repr
+
+
+CSS_FILE_PATH = "/".join(("static", "css", "style.css"))
+CSS_STYLE = pkg_resources.resource_string("xarray", CSS_FILE_PATH).decode("utf8")
+
+
+ICONS_SVG_PATH = "/".join(("static", "html", "icons-svg-inline.html"))
+ICONS_SVG = pkg_resources.resource_string("xarray", ICONS_SVG_PATH).decode("utf8")
+
+
+def short_data_repr_html(array):
+    """Format "data" for DataArray and Variable."""
+    internal_data = getattr(array, "variable", array)._data
+    if hasattr(internal_data, "_repr_html_"):
+        return internal_data._repr_html_()
+    return escape(short_data_repr(array))
+
+
+def format_dims(dims, coord_names):
+    if not dims:
+        return ""
+
+    dim_css_map = {
+        k: " class='xr-has-index'" if k in coord_names else "" for k, v in dims.items()
+    }
+
+    dims_li = "".join(
+        f"<li><span{dim_css_map[dim]}>" f"{escape(dim)}</span>: {size}</li>"
+        for dim, size in dims.items()
+    )
+
+    return f"<ul class='xr-dim-list'>{dims_li}</ul>"
+
+
+def summarize_attrs(attrs):
+    attrs_dl = "".join(
+        f"<dt><span>{escape(k)} :</span></dt>" f"<dd>{escape(str(v))}</dd>"
+        for k, v in attrs.items()
+    )
+
+    return f"<dl class='xr-attrs'>{attrs_dl}</dl>"
+
+
+def _icon(icon_name):
+    # icon_name should be defined in xarray/static/html/icon-svg-inline.html
+    return (
+        "<svg class='icon xr-{0}'>"
+        "<use xlink:href='#{0}'>"
+        "</use>"
+        "</svg>".format(icon_name)
+    )
+
+
+def _summarize_coord_multiindex(name, coord):
+    preview = f"({', '.join(escape(l) for l in coord.level_names)})"
+    return summarize_variable(
+        name, coord, is_index=True, dtype="MultiIndex", preview=preview
+    )
+
+
+def summarize_coord(name, var):
+    is_index = name in var.dims
+    if is_index:
+        coord = var.variable.to_index_variable()
+        if coord.level_names is not None:
+            coords = {}
+            coords[name] = _summarize_coord_multiindex(name, coord)
+            for lname in coord.level_names:
+                var = coord.get_level_variable(lname)
+                coords[lname] = summarize_variable(lname, var)
+            return coords
+
+    return {name: summarize_variable(name, var, is_index)}
+
+
+def summarize_coords(variables):
+    coords = {}
+    for k, v in variables.items():
+        coords.update(**summarize_coord(k, v))
+
+    vars_li = "".join(f"<li class='xr-var-item'>{v}</li>" for v in coords.values())
+
+    return f"<ul class='xr-var-list'>{vars_li}</ul>"
+
+
+def summarize_variable(name, var, is_index=False, dtype=None, preview=None):
+    variable = var.variable if hasattr(var, "variable") else var
+
+    cssclass_idx = " class='xr-has-index'" if is_index else ""
+    dims_str = f"({', '.join(escape(dim) for dim in var.dims)})"
+    name = escape(name)
+    dtype = dtype or var.dtype
+
+    # "unique" ids required to expand/collapse subsections
+    attrs_id = "attrs-" + str(uuid.uuid4())
+    data_id = "data-" + str(uuid.uuid4())
+    disabled = "" if len(var.attrs) else "disabled"
+
+    preview = preview or escape(inline_variable_array_repr(variable, 35))
+    attrs_ul = summarize_attrs(var.attrs)
+    data_repr = short_data_repr_html(variable)
+
+    attrs_icon = _icon("icon-file-text2")
+    data_icon = _icon("icon-database")
+
+    return (
+        f"<div class='xr-var-name'><span{cssclass_idx}>{name}</span></div>"
+        f"<div class='xr-var-dims'>{dims_str}</div>"
+        f"<div class='xr-var-dtype'>{dtype}</div>"
+        f"<div class='xr-var-preview xr-preview'>{preview}</div>"
+        f"<input id='{attrs_id}' class='xr-var-attrs-in' "
+        f"type='checkbox' {disabled}>"
+        f"<label for='{attrs_id}' title='Show/Hide attributes'>"
+        f"{attrs_icon}</label>"
+        f"<input id='{data_id}' class='xr-var-data-in' type='checkbox'>"
+        f"<label for='{data_id}' title='Show/Hide data repr'>"
+        f"{data_icon}</label>"
+        f"<div class='xr-var-attrs'>{attrs_ul}</div>"
+        f"<pre class='xr-var-data'>{data_repr}</pre>"
+    )
+
+
+def summarize_vars(variables):
+    vars_li = "".join(
+        f"<li class='xr-var-item'>{summarize_variable(k, v)}</li>"
+        for k, v in variables.items()
+    )
+
+    return f"<ul class='xr-var-list'>{vars_li}</ul>"
+
+
+def collapsible_section(
+    name, inline_details="", details="", n_items=None, enabled=True, collapsed=False
+):
+    # "unique" id to expand/collapse the section
+    data_id = "section-" + str(uuid.uuid4())
+
+    has_items = n_items is not None and n_items
+    n_items_span = "" if n_items is None else f" <span>({n_items})</span>"
+    enabled = "" if enabled and has_items else "disabled"
+    collapsed = "" if collapsed or not has_items else "checked"
+    tip = " title='Expand/collapse section'" if enabled else ""
+
+    return (
+        f"<input id='{data_id}' class='xr-section-summary-in' "
+        f"type='checkbox' {enabled} {collapsed}>"
+        f"<label for='{data_id}' class='xr-section-summary' {tip}>"
+        f"{name}:{n_items_span}</label>"
+        f"<div class='xr-section-inline-details'>{inline_details}</div>"
+        f"<div class='xr-section-details'>{details}</div>"
+    )
+
+
+def _mapping_section(mapping, name, details_func, max_items_collapse, enabled=True):
+    n_items = len(mapping)
+    collapsed = n_items >= max_items_collapse
+
+    return collapsible_section(
+        name,
+        details=details_func(mapping),
+        n_items=n_items,
+        enabled=enabled,
+        collapsed=collapsed,
+    )
+
+
+def dim_section(obj):
+    dim_list = format_dims(obj.dims, list(obj.coords))
+
+    return collapsible_section(
+        "Dimensions", inline_details=dim_list, enabled=False, collapsed=True
+    )
+
+
+def array_section(obj):
+    # "unique" id to expand/collapse the section
+    data_id = "section-" + str(uuid.uuid4())
+    collapsed = ""
+    preview = escape(inline_variable_array_repr(obj.variable, max_width=70))
+    data_repr = short_data_repr_html(obj)
+    data_icon = _icon("icon-database")
+
+    return (
+        "<div class='xr-array-wrap'>"
+        f"<input id='{data_id}' class='xr-array-in' type='checkbox' {collapsed}>"
+        f"<label for='{data_id}' title='Show/hide data repr'>{data_icon}</label>"
+        f"<div class='xr-array-preview xr-preview'><span>{preview}</span></div>"
+        f"<pre class='xr-array-data'>{data_repr}</pre>"
+        "</div>"
+    )
+
+
+coord_section = partial(
+    _mapping_section,
+    name="Coordinates",
+    details_func=summarize_coords,
+    max_items_collapse=25,
+)
+
+
+datavar_section = partial(
+    _mapping_section,
+    name="Data variables",
+    details_func=summarize_vars,
+    max_items_collapse=15,
+)
+
+
+attr_section = partial(
+    _mapping_section,
+    name="Attributes",
+    details_func=summarize_attrs,
+    max_items_collapse=10,
+)
+
+
+def _obj_repr(header_components, sections):
+    header = f"<div class='xr-header'>{''.join(h for h in header_components)}</div>"
+    sections = "".join(f"<li class='xr-section-item'>{s}</li>" for s in sections)
+
+    return (
+        "<div>"
+        f"{ICONS_SVG}<style>{CSS_STYLE}</style>"
+        "<div class='xr-wrap'>"
+        f"{header}"
+        f"<ul class='xr-sections'>{sections}</ul>"
+        "</div>"
+        "</div>"
+    )
+
+
+def array_repr(arr):
+    dims = OrderedDict((k, v) for k, v in zip(arr.dims, arr.shape))
+
+    obj_type = "xarray.{}".format(type(arr).__name__)
+    arr_name = "'{}'".format(arr.name) if getattr(arr, "name", None) else ""
+    coord_names = list(arr.coords) if hasattr(arr, "coords") else []
+
+    header_components = [
+        "<div class='xr-obj-type'>{}</div>".format(obj_type),
+        "<div class='xr-array-name'>{}</div>".format(arr_name),
+        format_dims(dims, coord_names),
+    ]
+
+    sections = [array_section(arr)]
+
+    if hasattr(arr, "coords"):
+        sections.append(coord_section(arr.coords))
+
+    sections.append(attr_section(arr.attrs))
+
+    return _obj_repr(header_components, sections)
+
+
+def dataset_repr(ds):
+    obj_type = "xarray.{}".format(type(ds).__name__)
+
+    header_components = [f"<div class='xr-obj-type'>{escape(obj_type)}</div>"]
+
+    sections = [
+        dim_section(ds),
+        coord_section(ds.coords),
+        datavar_section(ds.data_vars),
+        attr_section(ds.attrs),
+    ]
+
+    return _obj_repr(header_components, sections)

xarray/core/options.py

@@ -8,6 +8,7 @@
 CMAP_SEQUENTIAL = "cmap_sequential"
 CMAP_DIVERGENT = "cmap_divergent"
 KEEP_ATTRS = "keep_attrs"
+DISPLAY_STYLE = "display_style"
 
 
 OPTIONS = {
@@ -19,9 +20,11 @@
     CMAP_SEQUENTIAL: "viridis",
     CMAP_DIVERGENT: "RdBu_r",
     KEEP_ATTRS: "default",
+    DISPLAY_STYLE: "text",
 }
 
 _JOIN_OPTIONS = frozenset(["inner", "outer", "left", "right", "exact"])
+_DISPLAY_OPTIONS = frozenset(["text", "html"])
 
 
 def _positive_integer(value):
@@ -35,6 +38,7 @@ def _positive_integer(value):
     FILE_CACHE_MAXSIZE: _positive_integer,
     WARN_FOR_UNCLOSED_FILES: lambda value: isinstance(value, bool),
     KEEP_ATTRS: lambda choice: choice in [True, False, "default"],
+    DISPLAY_STYLE: _DISPLAY_OPTIONS.__contains__,
 }
 
 
@@ -98,6 +102,9 @@ class set_options:
       attrs, ``False`` to always discard them, or ``'default'`` to use original
       logic that attrs should only be kept in unambiguous circumstances.
       Default: ``'default'``.
+    - ``display_style``: display style to use in jupyter for xarray objects.
+      Default: ``'text'``. Other options are ``'html'``.
+
 
     You can use ``set_options`` either as a context manager: