minor updates

docs/user-guide/misc/visualization.md

@@ -57,6 +57,9 @@ To create a scatter plot we can pass columns of a `DataFrame` directly to Matplo
 Matplotlib does not have explicit support for Polars objects but can accept a Polars `Series` by
 converting it to a NumPy array (which is zero-copy for numeric data without null values).
 
+Note that because the column `'species'` isn't numeric, we need to first convert it to numeric values so that
+it can be passed as an argument to `c`.
+
 {{code_block('user-guide/misc/visualization','matplotlib_show_plot',[])}}
 
 ```python exec="on" session="user-guide/misc/visualization"

py-polars/polars/dataframe/plotting.py

@@ -80,7 +80,7 @@ def bar(
         color
             Column to color bars by.
         tooltip
-            Columns to show values of when hovering over points with pointer.
+            Columns to show values of when hovering over bars with pointer.
         *args, **kwargs
             Additional arguments and keyword arguments passed to Altair.
 
@@ -94,7 +94,7 @@ def bar(
         ...         "stock": ["a", "a", "a", "b", "b", "b"],
         ...     }
         ... )
-        >>> df.plot.line(x="date", y="price", color="stock")  # doctest: +SKIP
+        >>> df.plot.bar(x="price", y="count()")  # doctest: +SKIP
         """
         encodings: Encodings = {}
         if x is not None:
@@ -145,7 +145,7 @@ def line(
         order
             Column to use for order of data points in lines.
         tooltip
-            Columns to show values of when hovering over points with pointer.
+            Columns to show values of when hovering over lines with pointer.
         *args, **kwargs
             Additional arguments and keyword arguments passed to Altair.