if statement changes

Author: ZanirP

pandas/core/reshape/melt.py

@@ -173,9 +173,7 @@ def melt(
     1      b          B          E      3
     2      c          B          E      5
     """
-    # GH61475 - prevent AttributeError when duplicate column in id_vars
-    if id_vars and any(frame.columns.tolist().count(col) > 1 for col in id_vars):
-        raise ValueError("id_vars cannot contain duplicate columns.")
+
     if value_name in frame.columns:
         raise ValueError(
             f"value_name ({value_name}) cannot match an element in "
@@ -185,6 +183,10 @@ def melt(
     value_vars_was_not_none = value_vars is not None
     value_vars = ensure_list_vars(value_vars, "value_vars", frame.columns)
 
+    # GH61475 - prevent AttributeError when duplicate column in id_vars
+    if len(frame.columns.get_indexer_for(id_vars)) > len(id_vars):
+        raise ValueError("id_vars cannot contain duplicate columns.")
+
     if id_vars or value_vars:
         if col_level is not None:
             level = frame.columns.get_level_values(col_level)