ava6969 commented on issue #33834:
URL: https://github.com/apache/arrow/issues/33834#issuecomment-1400834195
so i just found this function . i am manipulating to what i want
pd::DataFrame joinOnIndex(pd::DataFrame const& left_table,
pd::DataFrame const& right_table,
bool ignore_index)
{
// Convert DataFrames to tables
auto unique_index =
std::to_string(std::chrono::high_resolution_clock::now().time_since_epoch().count())
+ "index";
auto left_table_as_table = left_table.toTable(unique_index);
auto right_table_as_table = right_table.toTable(unique_index);
// Define merge options for columns in case of name conflicts
arrow::Field::MergeOptions merge_options;
merge_options.promote_nullability = true; // Rename conflicting columns
// Concatenate tables
arrow::ConcatenateTablesOptions options;
options.unify_schemas = true; // Automatically merge schemas of tables
options.field_merge_options = merge_options; // Use defined merge
options for columns
auto table = pd::ReturnOrThrowOnFailure(arrow::ConcatenateTables(
{ left_table_as_table, right_table_as_table },
options));
auto merged_rb =
pd::ReturnOrThrowOnFailure(table->CombineChunksToBatch());
auto index_column_i = merged_rb->schema()->GetFieldIndex(unique_index);
auto index = merged_rb->column(index_column_i);
merged_rb = pd::ReturnOrThrowOnFailure(
merged_rb->RemoveColumn(index_column_i) );
if(ignore_index)
{
return merged_rb;
}
else
{
return { merged_rb, index };
}
}
using namespace pd;
using namespace string_literals;
using std::pair;
using std::vector;
int main()
{
auto df1 = pd::DataFrame(NULL_INDEX,
pair{"letter"s, vector{"a"s, "b"s}},
pair{"number"s, vector{1, 2}});
auto df2 = pd::DataFrame(NULL_INDEX,
pair{"letter"s, vector{"c"s, "d"s}},
pair{"number"s, vector{3, 4}});
auto df3 = pd::DataFrame(NULL_INDEX,
pair{"letter"s, vector{"c"s, "d"s}},
pair{"number"s, vector{3, 4}},
pair{"animal"s, vector{"cat"s, "dog"s}});
std::cout << joinOnIndex(df1, df2, false) << "\n";
std::cout << joinOnIndex(df1, df2, true) << "\n";
std::cout << joinOnIndex(df1, df3, false) << "\n";
return 0;
}
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