Constructornew Create a new instance. Optionally can be given a hash containing information from a header item or
the card image itself.
$item = new Astro::FITS::Header::Item( Card => $card );
$item = new Astro::FITS::Header::Item( Keyword => $keyword,
Value => $value );
The list of allowed hash keys is documented in the configure method.
Returns "undef" if the information supplied was insufficient to generate a valid header item.
copy
Make a copy of an Astro::FITS::Header::Item object.
$newitem = $item->copy;
AccessorMethodskeyword
Return (or set) the value of the keyword associated with the FITS card.
$keyword = $item->keyword();
$item->keyword( $key );
When a new value is supplied any "card" in the cache is invalidated.
Supplied value is always upper-cased.
value
Return (or set) the value of the value associated with the FITS card.
$value = $item->value();
$item->value( $val );
When a new value is supplied any "card" in the cache is invalidated.
If the value is an "Astro::FITS::Header" object, the type is automatically set to "HEADER".
comment
Return (or set) the value of the comment associated with the FITS card.
$comment = $item->comment();
$item->comment( $comment );
When a new value is supplied any "card" in the cache is invalidated.
type
Return (or set) the value of the variable type associated with the FITS card.
$type = $item->type();
$item->type( "INT" );
Allowed types are "LOGICAL", "INT", "FLOAT", "STRING", "COMMENT", "HEADER" and "UNDEF".
The special type, "HEADER", is used to specify that this item refers to a subsidiary header (eg a
header in an MEFITS file or a header in an NDF in an HDS container). See also the "subhdrs" method in
"Astro::FITS::Header" for an alternative way of specifying a sub-header.
The type is case-insensitive, but will always be returned up-cased.
card
Return (or set) the 80 character header card associated with this object. It is created if there is
no cached version.
$card = $item->card();
If a new card is supplied it will only be accepted if it is 80 characters long or fewer. The string
is padded with spaces if it is too short. No attempt (yet) )is made to shorten the string if it is
too long since that may require a check to see if the value is a string that must be shortened with a
closing single quote. Returns "undef" on assignment failure (else returns the supplied string).
$status = $item->card( $card );
"undef" is returned if there is insufficient information in the object to create a new card. Can
assign "undef" to clear the cache.
This method is called automatically when attempting to stringify the object.
$card = "$item";
GeneralMethodsconfigure
Configures the object from multiple pieces of information.
$item->configure( %options );
Takes a hash as argument with the following keywords:
Card If supplied, the value is assumed to be a standard 80 character FITS header card. This is
sent to the "parse_card" method directly. Takes priority over any other key.
If it is an "Astro::FITS::Header::Item" it will be copied rather than parsed.
Keyword Used to specify the keyword associated with this object.
Value Used to specify the value associated with this FITS item.
Comment Used to specify the comment associated with this FITS item.
Type Used to specify the variable type. See the "type" method for more details. A type will be
guessed if one is not supplied. The guess may well be wrong.
Does nothing if these keys are not supplied.
freeze
Method to return a blessed reference to the object so that we can store ths object on disk using
Data::Dumper module.
parse_card
Parse a FITS card image and store the keyword, value and comment into the object.
($key, $val, $com) = $item->parse_card( $card );
Returns an empty list on error.
equals
Compares this Item with another and returns true if the keyword, value, type and comment are all
equal.
$isident = $item->equals( $item2 );
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