melt moved into its own module (#18148)

Author: tdpetrou

pandas/core/api.py

@@ -24,8 +24,8 @@
 from pandas.core.panel import Panel, WidePanel
 from pandas.core.panel4d import Panel4D
 from pandas.core.reshape.reshape import (
-    pivot_simple as pivot, get_dummies,
-    lreshape, wide_to_long)
+    pivot_simple as pivot, get_dummies)
+from pandas.core.reshape.melt import lreshape, wide_to_long
 
 from pandas.core.indexing import IndexSlice
 from pandas.core.tools.numeric import to_numeric

pandas/core/frame.py

@@ -4637,7 +4637,7 @@ def unstack(self, level=-1, fill_value=None):
                    other='melt'))
     def melt(self, id_vars=None, value_vars=None, var_name=None,
              value_name='value', col_level=None):
-        from pandas.core.reshape.reshape import melt
+        from pandas.core.reshape.melt import melt
         return melt(self, id_vars=id_vars, value_vars=value_vars,
                     var_name=var_name, value_name=value_name,
                     col_level=col_level)

pandas/core/reshape/api.py

@@ -1,7 +1,7 @@
 # flake8: noqa
 
 from pandas.core.reshape.concat import concat
-from pandas.core.reshape.reshape import melt
+from pandas.core.reshape.melt import melt
 from pandas.core.reshape.merge import (
     merge, ordered_merge, merge_ordered, merge_asof)
 from pandas.core.reshape.pivot import pivot_table, crosstab