Method test_header_column_names

python/pyarrow/tests/test_csv.py:837–886

(self)

                }

    def test_header_column_names(self):
        rows = b"ab,cd\nef,gh\nij,kl\nmn,op\n"

        opts = ReadOptions()
        opts.column_names = ["x", "y"]
        table = self.read_bytes(rows, read_options=opts)
        self.check_names(table, ["x", "y"])
        assert table.to_pydict() == {
            "x": ["ab", "ef", "ij", "mn"],
            "y": ["cd", "gh", "kl", "op"],
        }

        opts.skip_rows = 3
        table = self.read_bytes(rows, read_options=opts)
        self.check_names(table, ["x", "y"])
        assert table.to_pydict() == {
            "x": ["mn"],
            "y": ["op"],
        }

        opts.skip_rows = 4
        table = self.read_bytes(rows, read_options=opts)
        self.check_names(table, ["x", "y"])
        assert table.to_pydict() == {
            "x": [],
            "y": [],
        }

        opts.skip_rows = 5
        with pytest.raises(pa.ArrowInvalid):
            # Not enough rows
            table = self.read_bytes(rows, read_options=opts)

        # Unexpected number of columns
        opts.skip_rows = 0
        opts.column_names = ["x", "y", "z"]
        with pytest.raises(pa.ArrowInvalid,
                           match="Expected 3 columns, got 2"):
            table = self.read_bytes(rows, read_options=opts)

        # Can skip rows with a different number of columns
        rows = b"abcd\n,,,,,\nij,kl\nmn,op\n"
        opts.skip_rows = 2
        opts.column_names = ["x", "y"]
        table = self.read_bytes(rows, read_options=opts)
        self.check_names(table, ["x", "y"])
        assert table.to_pydict() == {
            "x": ["ij", "mn"],
            "y": ["kl", "op"],
        }

    def test_header_autogenerate_column_names(self):
        rows = b"ab,cd\nef,gh\nij,kl\nmn,op\n"