keypar: Copy an image or table header keyword to an IRAF parameter.

Package: nttools

Usage

keypar input keyword

Description

This task reads a header keyword from an image or table file. The keyword is written to the IRAF parameter 'value' as a character string. If the header keyword is boolean, the value of 'value' will either be "yes" or "no". If the header keyword is not found, 'value' will be set to a null string. String parameters, such as 'value', can be converted to numeric data types with the built in functions real() and int().

Parameters

input [file name]

Name of the file containing the header keyword.

keyword [string]

Name of the header keyword to be retrieved. (The keyword name is not case sensitive.)

(silent = no) [bool]

If this parameter is set to no (the default) a warning message will be printed if the keyword is not found in the header. If it is set to yes, the warning message is suppressed.

(value) [string]

An output parameter that will contain the value passed from the header keyword.

(found) [bool]

An output parameter that will be set to yes if the keyword is found in the header and no if it is not.

Examples

1. Print the number of groups (i.e., the 'GCOUNT' keyword) in the image file 'image.hhh':

tt> keypar image.hhh gcount
tt> print(keypar.value)

2. Print the range of the data in the second group of the same image by reading the values of the 'DATAMIN' and 'DATAMAX' keywords:

tt> keypar image.hhh[2] datamin
tt> x = real(keypar.value)
tt> keypar image.hhh[2] datamax
tt> y = real(keypar.value)
tt> print(y-x)

3. Print the component name (i.e., the 'COMPNAME' header keyword) for the table 'thruput.tab':

tt> keypar thruput.tab compname
tt> print(keypar.value)

4. Check for the existence of the exposure time in an image header:

tt> keypar image.hhh exptime silent+
tt> if (keypar.found) {
>>> print keypar.value
>>> } else {
>>> print INDEF
>>> }

References

This task was written by Bernie Simon. SEE ALSO keytab, parkey, partab, tabkey, tabpar