pandas-dev#7211 @dsm2173 @jmp392 updated KeyError text to be more informative in this particular common error type

Author: dm2173

pandas/_libs/hashtable_class_helper.pxi.in

@@ -856,7 +856,7 @@ cdef class PyObjectHashTable(HashTable):
         if k != self.table.n_buckets:
             return self.table.vals[k]
         else:
-            raise KeyError(val)
+            raise KeyError("Column with name \"{}\" is not found. Did you mean \"df[{}:]\" ?".format(val,val))
 
     cpdef set_item(self, object key, Py_ssize_t val):
         cdef: