Name

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F_FORMAT

Purpose

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Choose a nice floating format for displaying an array of REAL data.

Explanation

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Called by TVLIST, IMLIST.

Calling Sequence

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fmt = F_FORMAT( minval, maxval, factor, [ length ] )

Inputs

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MINVAL - REAL scalar giving the minimum value of an array of numbers
for which one desires a nice format.
MAXVAL - REAL scalar giving maximum value in array of numbers

Optional Input

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LENGTH - length of the output F format (default = 5)
must be an integer scalar > 2

Output

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FMT - an F or I format string, e.g. 'F5.1'
FACTOR - factor of 10 by which to multiply array of numbers to achieve
a pretty display using format FMT.

Example

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Find a nice format to print an array of numbers with a minimum of 5.2e-3
and a maximum of 4.2e-2.
IDL> fmt = F_FORMAT( 5.2e-3, 4.2e-2, factor )
       
yields fmt = '(F5.2)' and factor = .01, i.e. the array can be displayed
with a F5.2 format after multiplication by 100.

Revision History

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Written W. Landsman December 1988
Deal with factors < 1. August 1991
Deal with factors < 1. *and* a large range October 1992
Now returns In format rather than Fn.0 February, 1994
Converted to IDL V5.0 W. Landsman September 1997