Delay matplotlib import

Author: TomAugspurger

pandas/plotting/__init__.py

@@ -4,12 +4,6 @@
 
 # flake8: noqa
 
-try:  # mpl optional
-    from pandas.plotting import _converter
-    _converter.register()  # needs to override so set_xlim works with str/number
-except ImportError:
-    pass
-
 from pandas.plotting._misc import (scatter_matrix, radviz,
                                    andrews_curves, bootstrap_plot,
                                    parallel_coordinates, lag_plot,

pandas/plotting/_core.py

@@ -39,12 +39,7 @@
                                     _get_xlim, _set_ticks_props,
                                     format_date_labels)
 
-
-if _mpl_ge_1_5_0():
-    # Compat with mp 1.5, which uses cycler.
-    import cycler
-    colors = mpl_stylesheet.pop('axes.color_cycle')
-    mpl_stylesheet['axes.prop_cycle'] = cycler.cycler('color', colors)
+_registered = False
 
 
 def _get_standard_kind(kind):
@@ -94,6 +89,7 @@ def __init__(self, data, kind=None, by=None, subplots=False, sharex=None,
                  secondary_y=False, colormap=None,
                  table=False, layout=None, **kwds):
 
+        self._setup()
         self.data = data
         self.by = by
 
@@ -177,6 +173,20 @@ def __init__(self, data, kind=None, by=None, subplots=False, sharex=None,
 
         self._validate_color_args()
 
+    def _setup(self):
+        global _registered
+        if not _registered:
+            from pandas.plotting import _converter
+            _converter.register()
+
+            if _mpl_ge_1_5_0():
+                # Compat with mp 1.5, which uses cycler.
+                import cycler
+                colors = mpl_stylesheet.pop('axes.color_cycle')
+                mpl_stylesheet['axes.prop_cycle'] = cycler.cycler('color', colors)
+
+            _registered = True
+
     def _validate_color_args(self):
         if 'color' not in self.kwds and 'colors' in self.kwds:
             warnings.warn(("'colors' is being deprecated. Please use 'color'"