pandas.HDFStore.append — pandas 3.0.0.dev0+2104.ge637b4290d documentation (original) (raw)
HDFStore.append(key, value, format=None, axes=None, index=True, append=True, complib=None, complevel=None, columns=None, min_itemsize=None, nan_rep=None, chunksize=None, expectedrows=None, dropna=None, data_columns=None, encoding=None, errors='strict')[source]#
Append to Table in file.
Node must already exist and be Table format.
Parameters:
keystr
Key of object to append.
value{Series, DataFrame}
Value of object to append.
format‘table’ is the default
Format to use when storing object in HDFStore. Value can be one of:
'table'
Table format. Write as a PyTables Table structure which may perform worse but allow more flexible operations like searching / selecting subsets of the data.
axesdefault None
This parameter is currently not accepted.
indexbool, default True
Write DataFrame index as a column.
appendbool, default True
Append the input data to the existing.
complibdefault None
This parameter is currently not accepted.
complevelint, 0-9, default None
Specifies a compression level for data. A value of 0 or None disables compression.
columnsdefault None
This parameter is currently not accepted, try data_columns.
min_itemsizeint, dict, or None
Dict of columns that specify minimum str sizes.
nan_repstr
Str to use as str nan representation.
chunksizeint or None
Size to chunk the writing.
expectedrowsint
Expected TOTAL row size of this table.
dropnabool, default False, optional
Do not write an ALL nan row to the store settable by the option ‘io.hdf.dropna_table’.
data_columnslist of columns, or True, default None
List of columns to create as indexed data columns for on-disk queries, or True to use all columns. By default only the axes of the object are indexed. See here.
encodingdefault None
Provide an encoding for str.
errorsstr, default ‘strict’
The error handling scheme to use for encoding errors. The default is ‘strict’ meaning that encoding errors raise a UnicodeEncodeError. Other possible values are ‘ignore’, ‘replace’ and ‘xmlcharrefreplace’ as well as any other name registered with codecs.register_error that can handle UnicodeEncodeErrors.
See also
HDFStore.append_to_multiple
Append to multiple tables.
Notes
Does not check if data being appended overlaps with existing data in the table, so be careful
Examples
df1 = pd.DataFrame([[1, 2], [3, 4]], columns=["A", "B"]) store = pd.HDFStore("store.h5", "w")
store.put("data", df1, format="table")
df2 = pd.DataFrame([[5, 6], [7, 8]], columns=["A", "B"]) store.append("data", df2)
store.close()
A B 0 1 2 1 3 4 0 5 6 1 7 8