YAML table writer class

class pytablewriter.YamlTableWriter(**kwargs)[source]

Bases: pytablewriter.writer.text._text_writer.TextTableWriter

A table writer class for YAML format.



add_style_filter(style_filter: pytablewriter.style._theme.StyleFilterFunc) None

Add a style filter function to the writer.



A function that called for each cell in the table to apply a style to table cells. The function will be required to implement the following Protocol:

class StyleFilterFunc(Protocol):
    def __call__(self, cell: Cell, **kwargs: Any) -> Optional[Style]:

If more than one style filter function is added to the writer, it will be called from the last one added. These style functions should return None when not needed to apply styles. If all of the style functions returned None, default_style will be applied.

You can pass keyword arguments to style filter functions via style_filter_kwargs. In default, the attribute includes:

  • writer: the writer instance that the caller of a style_filter function

clear_theme() None

Remove all of the style filters.

close() None

Close the current stream.

property column_styles: List[Optional[pytablewriter.style._style.Style]]

Output Style for each column.

Return type

list of Style

property default_style: pytablewriter.style._style.Style

Default Style of table cells.

dump(output: Union[str, IO], close_after_write: bool = True, **kwargs) None

Write data to the output with tabular format.

During the executing this method, enable_ansi_escape attribute will be temporarily set to False.

  • output – The value must either an output stream or a path to an output file.

  • close_after_write – Close the output after write. Defaults to True.

dumps(**kwargs) str

Get rendered tabular text from the table data.

Only available for text format table writers.


**kwargs – Optional arguments that the writer takes.


Rendered tabular text.

Return type


property format_name: str

Format name for the writer.



from_csv(csv_source: str, delimiter: str = ',') None

Set tabular attributes to the writer from a character-separated values (CSV) data source. Following attributes are set to the writer by the method:

table_name also be set if the CSV data source is a file. In that case, table_name is as same as the filename.


csv_source (str) – Input CSV data source either can be designated CSV text or CSV file path.


Using CSV as tabular data source

Dependency Packages
from_dataframe(dataframe, add_index_column: bool = False, overwrite_type_hints: bool = True) None

Set tabular attributes to the writer from pandas.DataFrame. Following attributes are set by the method:

  • dataframe (pandas.DataFrame or str) – Input pandas.DataFrame object or pickle.

  • add_index_column (bool, optional) – If True, add a column of index of the dataframe. Defaults to False.

  • overwrite_type_hints (bool) – If True, Overwrite type hints with dtypes within the DataFrame.


Using pandas DataFrame as tabular data source

from_series(series, add_index_column: bool = True) None

Set tabular attributes to the writer from pandas.Series. Following attributes are set by the method:

  • series (pandas.Series) – Input pandas.Series object.

  • add_index_column (bool, optional) – If True, add a column of index of the series. Defaults to True.

from_tabledata(value: tabledata._core.TableData, is_overwrite_table_name: bool = True) None

Set tabular attributes to the writer from TableData. Following attributes are configured:

TableData can be created from various data formats by pytablereader. More detailed information can be found in https://pytablereader.rtfd.io/en/latest/


value (tabledata.TableData) – Input table data.

from_tablib(tablib_dataset) None

Set tabular attributes to the writer from tablib.Dataset.

from_writer(writer: pytablewriter.writer._table_writer.AbstractTableWriter, is_overwrite_table_name: bool = True) None

Set tabular attributes to the writer from an another table writer class incetance.

property headers: Sequence[str]

Headers of a table to be outputted.

set_style(column: Union[str, int], style: pytablewriter.style._style.Style) None

Set Style for a specific column.

  • column (int or str) – Column specifier. column index or header name correlated with the column.

  • style (Style) – Style value to be set to the column.


ValueError – If the column specifier is invalid.

set_theme(theme: str, **kwargs) None

Set style filters for a theme.


theme (str) – Name of the theme. pytablewriter theme plugin must be installed corresponding to the theme name.


RuntimeError – Raised when a theme plugin does not installed.

property support_split_write: bool

Represents the writer class supported iterative table writing (write_table_iter method).


True if the writer supported iterative table writing.

Return type


property table_format

Get the format of the writer.

Return type


property table_name: str

Name of a table.

property tabledata: tabledata._core.TableData

Get tabular data of the writer.

Return type


property type_hints: List[Optional[Type[typepy.type._base.AbstractType]]]

Type hints for each column of the tabular data. Writers convert data for each column using the type hints information before writing tables when you call write_xxx methods.

Acceptable values are as follows:

  • None (automatically detect column type from values in the column)

  • pytablewriter.typehint.Bool or "bool"

  • pytablewriter.typehint.DateTime or "datetime"

  • pytablewriter.typehint.Dictionary or "dict"

  • pytablewriter.typehint.Infinity or "inf"

  • pytablewriter.typehint.Integer or "int"

  • pytablewriter.typehint.IpAddress or "ipaddr"

  • pytablewriter.typehint.List or "list"

  • pytablewriter.typehint.Nan or "nan"

  • pytablewriter.typehint.NoneType or "none"

  • pytablewriter.typehint.NullString or "nullstr"

  • pytablewriter.typehint.RealNumber or "realnumber" or "float"

  • pytablewriter.typehint.String or "str"

If a type-hint value is not None, the writer tries to convert data for each data in a column to type-hint class. If the type-hint value is None or failed to convert data, the writer automatically detect column data type from the column data.

If type_hints is None, the writer detects data types for all of the columns automatically and writes a table by using detected column types.

Defaults to None.

property value_matrix: Sequence

Data of a table to be outputted.

write_null_line() None

Write a null line to the stream.

write_table(**kwargs) None[source]

Write a table to the stream with YAML format.



write_table_iter(**kwargs) None

Write a table with iteration. “Iteration” means that divide the table writing into multiple processes. This method is useful, especially for large data. The following are premises to execute this method:

  • set iterator to the value_matrix

  • set the number of iterations to the iteration_length attribute

Call back function (Optional): Callback function is called when for each of the iteration of writing a table is completed. To set call back function, set a callback function to the write_callback attribute.


pytablewriter.NotSupportedError – If the class does not support this method.


Following classes do not support this method: HtmlTableWriter, RstGridTableWriter, RstSimpleTableWriter. support_split_write attribute return True if the class is supporting this method.