Added enable_string_cache, disable_string_cache, and using_string_cac…

…he to Polars

CHANGELOG.md

@@ -8,6 +8,7 @@ See the [upgrade guide](https://docs.pola.rs/releases/upgrade/0.20/)
 - Added `Enum` type
 - Added `Testing` module
 - Added `arctan2`, `arctan2d`, `set_random_seed`, and `sql_expr` methods to `Polars`
+- Added `enable_string_cache`, `disable_string_cache`, and `using_string_cache` to `Polars`
 - Added methods for horizontal aggregations to `Polars`
 - Added `sink_ipc`, `sink_csv`, and `sink_ndjson` methods to `LazyFrame`
 - Added `replace` method to `Series` and `Expr`

lib/polars.rb

@@ -55,6 +55,7 @@
 require_relative "polars/series"
 require_relative "polars/slice"
 require_relative "polars/sql_context"
+require_relative "polars/string_cache"
 require_relative "polars/string_expr"
 require_relative "polars/string_name_space"
 require_relative "polars/struct_expr"

lib/polars/string_cache.rb

@@ -0,0 +1,68 @@
+module Polars
+  module Functions
+    # Enable the global string cache.
+    #
+    # `Categorical` columns created under the same global string cache have
+    # the same underlying physical value when string values are equal. This allows the
+    # columns to be concatenated or used in a join operation, for example.
+    #
+    # @return [nil]
+    #
+    # @example Construct two Series using the same global string cache.
+    #   Polars.enable_string_cache
+    #   s1 = Polars::Series.new("color", ["red", "green", "red"], dtype: Polars::Categorical)
+    #   s2 = Polars::Series.new("color", ["blue", "red", "green"], dtype: Polars::Categorical)
+    #   Polars.disable_string_cache
+    #
+    # @example As both Series are constructed under the same global string cache, they can be concatenated.
+    #   Polars.concat([s1, s2])
+    #   # =>
+    #   # shape: (6,)
+    #   # Series: 'color' [cat]
+    #   # [
+    #   #         "red"
+    #   #         "green"
+    #   #         "red"
+    #   #         "blue"
+    #   #         "red"
+    #   #         "green"
+    #   # ]
+    def enable_string_cache
+      Plr.enable_string_cache
+    end
+
+    # Disable and clear the global string cache.
+    #
+    # @return [nil]
+    #
+    # @example Construct two Series using the same global string cache.
+    #   Polars.enable_string_cache
+    #   s1 = Polars::Series.new("color", ["red", "green", "red"], dtype: Polars::Categorical)
+    #   s2 = Polars::Series.new("color", ["blue", "red", "green"], dtype: Polars::Categorical)
+    #   Polars.disable_string_cache
+    #
+    # @example As both Series are constructed under the same global string cache, they can be concatenated.
+    #   Polars.concat([s1, s2])
+    #   # =>
+    #   # shape: (6,)
+    #   # Series: 'color' [cat]
+    #   # [
+    #   #         "red"
+    #   #         "green"
+    #   #         "red"
+    #   #         "blue"
+    #   #         "red"
+    #   #         "green"
+    #   # ]
+    def disable_string_cache
+      Plr.disable_string_cache
+    end
+
+    # Check whether the global string cache is enabled.
+    #
+    # @return [Boolean]
+    def using_string_cache
+      Plr.using_string_cache
+    end
+  end
+end