Downsampling

Downsampling#

When an interactive table is displayed by itables, the table data is embedded into the notebook itself. Large tables need to be downsampled, otherwise your notebook will become huge and unresponsive.

Downsampling occurs when the table data is larger than maxBytes, which is equal to 64KB by default. When downsampling occurs, a warning is displayed below the table, which points to the itables documentation.

If you wish, you can increase the value of maxBytes or even deactivate the limit (with maxBytes=0) - but again, that will break your notebook when you display a large dataframe.

Similarly, you can set a limit on the number of rows (maxRows, defaults to 0) or columns (maxColumns, defaults to 200).

import itables

itables.init_notebook_mode()

init_notebook_modetrusted

itables.options.maxBytes = "8KB"

df = itables.sample_dfs.get_countries()
itables.downsample.as_nbytes(itables.options.maxBytes), itables.downsample.nbytes(df)

(8192, 8320)

df

^ⓘ	region	country	capital	longitude	latitude
code
AW	Latin America & Caribbean	Aruba	Oranjestad	-70.016700	12.516700
AF	South Asia	Afghanistan	Kabul	69.176100	34.522800
AO	Sub-Saharan Africa	Angola	Luanda	13.242000	-8.811550
AL	Europe & Central Asia	Albania	Tirane	19.817200	41.331700
AD	Europe & Central Asia	Andorra	Andorra la Vella	1.521800	42.507500
AE	Middle East & North Africa	United Arab Emirates	Abu Dhabi	54.370500	24.476400
AR	Latin America & Caribbean	Argentina	Buenos Aires	-58.417300	-34.611800
AM	Europe & Central Asia	Armenia	Yerevan	44.509000	40.159600
AS	East Asia & Pacific	American Samoa	Pago Pago	-170.691000	-14.284600
AG	Latin America & Caribbean	Antigua and Barbuda	Saint John's	-61.845600	17.117500
(198 more rows not shown)

To show the table in full, we can modify the value of maxBytes either locally:

itables.show(df, maxBytes=32768)

^ⓘ	region	country	capital	longitude	latitude
code
AW	Latin America & Caribbean	Aruba	Oranjestad	-70.016700	12.516700
AF	South Asia	Afghanistan	Kabul	69.176100	34.522800
AO	Sub-Saharan Africa	Angola	Luanda	13.242000	-8.811550
AL	Europe & Central Asia	Albania	Tirane	19.817200	41.331700
AD	Europe & Central Asia	Andorra	Andorra la Vella	1.521800	42.507500
AE	Middle East & North Africa	United Arab Emirates	Abu Dhabi	54.370500	24.476400
AR	Latin America & Caribbean	Argentina	Buenos Aires	-58.417300	-34.611800
AM	Europe & Central Asia	Armenia	Yerevan	44.509000	40.159600
AS	East Asia & Pacific	American Samoa	Pago Pago	-170.691000	-14.284600
AG	Latin America & Caribbean	Antigua and Barbuda	Saint John's	-61.845600	17.117500
(198 more rows not shown)

or globally:

itables.options.maxBytes = "1MB"
df

^ⓘ	region	country	capital	longitude	latitude
code
AW	Latin America & Caribbean	Aruba	Oranjestad	-70.016700	12.516700
AF	South Asia	Afghanistan	Kabul	69.176100	34.522800
AO	Sub-Saharan Africa	Angola	Luanda	13.242000	-8.811550
AL	Europe & Central Asia	Albania	Tirane	19.817200	41.331700
AD	Europe & Central Asia	Andorra	Andorra la Vella	1.521800	42.507500
AE	Middle East & North Africa	United Arab Emirates	Abu Dhabi	54.370500	24.476400
AR	Latin America & Caribbean	Argentina	Buenos Aires	-58.417300	-34.611800
AM	Europe & Central Asia	Armenia	Yerevan	44.509000	40.159600
AS	East Asia & Pacific	American Samoa	Pago Pago	-170.691000	-14.284600
AG	Latin America & Caribbean	Antigua and Barbuda	Saint John's	-61.845600	17.117500
(198 more rows not shown)