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string manipulation [message #23898]

Mon, 26 February 2001 14:34

Craig Markwardt
Messages: 1869
Registered: November 1996

Senior Member

I have been thinking about the following problem, but have been pretty
frustrated.

I have input keyword/value strings of the following form. People may
recognize this from a FITS file.

TTYPE2 = 'X1LSpecPcu0' / X1LSpecPcu0 : Histogram
TUNIT2 = 'count '
1CTYP2 = 'CHANNEL '
1CPIX2 = '0~4,5:53,(54~135;2),(136~237;3),(238~249;4),250~255'
12CD2A = 1.25
^name^^ ^value^^^^^^^

All of the keyword names have a trailing "2" which indicates that they
are describing column number 2 in a FITS table. Note that in the name
"12CD2A", only the *final* 2 refers to the column number.

The interesting question happens when I want to change the column
number, say from "2" to "50". Is there a straightforward way to do
this in "vectoral" sort of way?

I am able to find the string positions of the 2's, so that's not
really a problem. I do this by making a byte array of the strings,
and blanking out any alphabetic characters and any leading numeric
characters. Here I appreciate STRPOS is (partially) vectorized.

However, when it comes to resubstituting the "50" back in, that's when
I get stymied. This is primarily because STRMID and STRPUT are not
vectorized at all. Well STRMID *is* vectorized, but not with a sane
behavior. For example, what I'd like to do is:

NEWKEY = STRMID(KEY,0,P1) + '50' + STRMID(KEY,P2,100)

Where KEY, P1, and P2 are vectors. Obviously this doesn't work. Any
ideas?

Craig

--
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Craig B. Markwardt, Ph.D. EMAIL: craigmnet@cow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
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[Message index]

		string manipulation By: Craig Markwardt on Mon, 26 February 2001 14:34
		Re: string manipulation By: Kenneth P. Bowman on Wed, 28 February 2001 16:16
		Re: string manipulation By: Pavel A. Romashkin on Thu, 01 March 2001 11:54
		Re: string manipulation By: Mark Hadfield on Wed, 28 February 2001 12:30
		Re: string manipulation By: John-David T. Smith on Tue, 27 February 2001 16:35
		Re: string manipulation By: davidf on Tue, 27 February 2001 15:34
		Re: string manipulation By: Mark Hadfield on Tue, 27 February 2001 15:02
		Re: string manipulation By: John-David T. Smith on Tue, 27 February 2001 14:40
		Re: string manipulation By: landsman on Tue, 27 February 2001 13:29

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