String manipulation in IRAF

grayro wrote on Jan 20, 2017

Hi, I am having problems with some RA and DEC keywords in fxcor. fxcor wants the values to be delimited with colons, such as "12:30:56", but I have some spectra which have spaces instead: "12 30 56" and fxcor chokes on those. I want to be able to edit the header to correct those strings (by simple character replacement: replace " " with ":"), but I cannot find a string function in IRAF that will do that replacement. I could do this easily in "C", but do not see how to do this within IRAF. Can you help?

Richard

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Mike Fitzpatrick wrote on Jan 20, 2017

You can wrap it up in a script to process lists of images, but the basic steps would make use of the 'sed' foreign command in something like:

hselect ("foo.fits", "RA", yes) | sed("-e 's/ /:/g'") | scan (s1)

hedit ("foo.fits", "RA", s1, update+, verify-)

and then the same for the 'DEC" keyword. Unfortunately there isn't a string replacement function built directly into any of the header tasks.

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Last post on Jan 20, 2017