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Last modified: December 2009

URL: http://cxc-newtest.cfa.harvard.edu/ciao4.2/delete_key.sl.html
AHELP for CIAO 4.2

delete_key

Context: sl.crates

Synopsis

Delete a keyword from a crate.

Syntax

delete_key(crate, keyid);

Description

  • crate - input crate
  • keyid - key name or number, where the first key is numbered 0

The delete_key command removes the specified keyword from the crate. The print_key_names command ("ahelp print_key_names") lists all the keywords in the file with the corresponding numbers.

The command returns a "1" if the keyword is successfully deleted. The keyword is only deleted from the data in the crate; it's not removed from the input file. The write_file command ("ahelp write_file") can be used to save the modified crate to a file.

Example 1

slsh> cr = read_file("evt2.fits");
slsh> print (get_key_names(cr));
['TELESCOP' 'INSTRUME' 'DETNAME' 'FILTER' 'CHANTYPE' 'DETCHANS'...]
slsh> delete_key(cr, "FILTER");
1
slsh> key_exists(cr, "FILTER");
0
slsh> write_file(cr, "nofilt.fits");
1

Delete the FILTER keyword from the crate, then use the key_exists command to confirm it has been deleted. Write the crate to nofilt.fits.

Example 2

slsh> cr = read_file("evt2.fits");
slsh> delete_key(cr, 35);
1
slsh> key_exists(cr, "OBS_ID");
0
slsh> write_file(cr, "edit.fits");
1

Delete keyword number 35 - the OBS_ID keyword in this file - from the crate, then write the crate to file edit.fits.

Bugs

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

See Also

sl.crates
add_col, add_key, add_piximg, delete_col, delete_piximg, get_key, get_key_names, get_keyval, key_exists, print_key_names, read_arf, read_file, read_pha, read_rmf, set_keyval, write_arf, write_file, write_pha, write_rmf
sl.crates_contrib
make_table_crate, scale_image_crate, write_columns

Last modified: December 2009