.help keypar Dec94 tables
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NAME
keypar -- Copy a header keyword to an IRAF parameter.
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USAGE
keypar input keyword
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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().
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PARAMETERS
.ls input [file name]
Name of the file containing the header keyword.
.le
.ls keyword [string]
Name of the header keyword to be retrieved. (The keyword 
name is not case sensitive.)
.le
.ls (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.
.le
.ls (value) [string]
An output  parameter that will contain the value passed from the header
keyword.
.le
.ls (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.
.le
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EXAMPLES
1. Print the number of groups (i.e., the 'GCOUNT' keyword)
in the image file 'image.hhh':

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

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:

.nf
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)
.fi

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

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

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

.nf
tt> keypar image.hhh exptime silent+
tt> if (keypar.found) {
>>> print keypar.value
>>> } else {
>>> print INDEF
>>> }
.fi
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REFERENCES
This task was written by Bernie Simon.
SEE ALSO
keytab, parkey, partab, tabkey, tabpar
.endhelp
