Last modified: December 2023

AHELP for CIAO 4.16 Sherpa


Context: filtering


Return the filter expression for a data set.



id - int or str, optional


This returns the filter expression, created by one or more calls to `ignore` and `notice` , for the data set.


Example 1

The default filter is the full dataset, given in the format lowval:hival (for a `Data1D` dataset like this these are inclusive limits):

>>> load_arrays(1, [10, 15, 20, 25], [5, 7, 4, 2])
>>> get_filter()

Example 2

The `notice` call restricts the data to the range between 14 and 30. The resulting filter is the combination of this range and the data:

>>> notice(14, 30)
>>> get_filter()

Example 3

Ignoring the point at x=20 means that only the points at x=15 and x=25 remain, so a comma-separated list is used:

>>> ignore(19, 22)
>>> get_filter()

Example 4

The filter equivalent to the per-bin array of filter values:

>>> set_filter([1, 1, 0, 1])
>>> get_filter()

Example 5

For an integrated data set (Data1DInt and DataPHA with energy or wavelength units)

>>> load_arrays(1, [10, 15, 20, 25], [15, 20, 23, 30], [5, 7, 4, 2], Data1DInt)
>>> get_filter()

Example 6

For integrated datasets the limits are now inclusive only for the lower limit, but in this the end-point ends within a bin so is is included:

>>> notice(17, 28)
>>> get_filter()

Example 7

There is no data in the range 23 to 24 so the ignore doesn't change anything:

>>> ignore(23, 24)
>>> get_filter()

Example 8

However it does match the range 22 to 23 and so changes the filter:

>>> ignore(22, 23)
>>> get_filter()

Example 9

Return the filter for data set 3:

>>> get_filter(3)


The parameter for this function is:

Parameter Definition
id The identifier for the data set to use. If not given then the default identifier is used, as returned by `get_default_id` .

Return value

The return value from this function is:

filter -- The empty string or a string expression representing the filter used. For PHA data dets the units are controlled by the analysis setting for the data set.

Changes in CIAO

Changed in CIAO 4.14

The filter expressions have been tweaked for Data1DInt and PHA data sets (when using energy or wavelength units) and now describe the full range of the bins, rather than the mid-points.


See the bugs pages on the Sherpa website for an up-to-date listing of known bugs.

See Also

get_conf, get_conf_results, get_covar, get_covar_opt, get_covar_results, get_covariance_results, get_int_proj, get_int_unc, get_proj, get_proj_opt, get_proj_results, get_projection_results, get_reg_proj, get_reg_unc
get_chart_spectrum, get_marx_spectrum
copy_data, dataspace1d, dataspace2d, datastack, delete_data, fake, get_areascal, get_arf, get_arf_plot, get_axes, get_backscal, get_bkg, get_bkg_arf, get_bkg_chisqr_plot, get_bkg_delchi_plot, get_bkg_fit_plot, get_bkg_model, get_bkg_model_plot, get_bkg_plot, get_bkg_ratio_plot, get_bkg_resid_plot, get_bkg_rmf, get_bkg_scale, get_bkg_source, get_bkg_source_plot, get_coord, get_counts, get_data, get_data_contour, get_data_contour_prefs, get_data_image, get_data_plot, get_data_plot_prefs, get_dep, get_dims, get_error, get_exposure, get_grouping, get_indep, get_quality, get_rmf, get_specresp, get_staterror, get_syserror, group, group_adapt, group_adapt_snr, group_bins, group_counts, group_snr, group_width, load_ascii, load_data, load_grouping, load_quality, set_data, set_quality, ungroup, unpack_ascii, unpack_data
ignore, ignore2d, ignore2d_id, ignore_bad, ignore_id, load_filter, notice, notice2d, notice2d_id, notice_id, set_filter, show_filter
calc_stat_info, get_stat_info
get_default_id, list_data_ids, list_response_ids, list_stats
get_draws, get_iter_method_name, get_iter_method_opt, get_method, get_method_name, get_method_opt
clean, get_model, get_model_component, get_model_component_image, get_model_component_plot, get_model_plot, get_num_par, get_num_par_frozen, get_num_par_thawed, get_order_plot, get_par, get_pileup_model, get_response, get_source, get_source_component_image, get_source_component_plot, get_source_contour, get_source_image, get_source_plot, image_source
get_split_plot, plot_data, set_xlinear, set_xlog, set_ylinear, set_ylog
get_psf, get_psf_contour, get_psf_image, get_psf_plot
save_error, save_filter, save_grouping, save_quality, save_staterror, save_syserror
get_chisqr_plot, get_delchi_plot, get_prior, get_sampler, get_stat, get_stat_name
calc_data_sum, calc_data_sum2d, calc_ftest, calc_kcorr, calc_mlr, calc_model_sum2d, calc_source_sum2d, get_analysis, get_rate
contour, contour_data, contour_ratio, histogram1d, histogram2d, image_data, image_getregion, rebin