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Re: Import syntax question

• To: mathgroup at smc.vnet.net
• Subject: [mg85506] Re: [mg85440] Import syntax question
• From: "Igor C. Antonio" <igora at wolf-ram.com>
• Date: Wed, 13 Feb 2008 04:09:07 -0500 (EST)
• Organization: Wolfram Research, Inc.
• References: <200802101022.FAA18017@smc.vnet.net>
• Reply-to: igora at wolf-ram.com

Hi Mark,

You should do:

Import["file.pdf", {{"Author", "Title"}}] or

Import["file.pdf", {"PDF", {"Author", "Title"}].


The general syntaxes for extracting elements are:

Import["file", {"format", "elem1"}]
---> import elem1 of "file" imported as "format."

Import["file", {"format", "elem1", "subelem1", ...}]
---> When elem1 is itself a list of elements, you can import its "subelements."
This one means import the subelem1 of elem1 (when elem1 is a list of rules) of 
the "file" imported as "format."

Import["file", {"format", {"elem1", "elem2", "elem3"...}}]
---> This is the syntax for importing multiple elements.

To make things a little more confusing ;), there's a shorthand notation when the 
second argument is *only one string*:  You can omit the {}'s:

Import["file.pdf", "Author"]
Import["file.pdf", "Title"]

Import uses FileFormat[] for format detection if you don't explicitly specify 
the "format," but the {}'s must remain as shown above if your second argument 
contains more than one string.

Igor

--
Igor C. Antonio
Wolfram Research, Inc.
http://www.wolfram.com

To email me personally, remove the dash.


Mark Fisher wrote:
> Hi all,
> 
> I find Import wonderful but frustrating. For example, I can get
> individual items such as "Author" and "Title" in separate calls:
> 
> Import["file.pdf", "Author"]
> Import["file.pdf", "Title"]
> 
> but I can't get a list as in
> 
> Import["file.pdf", {"Author", "Title"}]
> 
> Instead I get an error message that say "Title" is not present (which
> seems misleading at best, since I already accessed it above). Is that
> syntax supposed to work or not? (Frankly, I'm having a hard time
> figuring out what the proper generic syntax is for Import, especially
> since there are so few examples in the documentation.)
> 
> BTW, I found out I can use
> 
> {"Author", "Title"} /. Import["file.pdf", "Rules"]
> 
> Is that what I "should" be doing? (It seems like overkill since Import
> has to import a bunch more stuff that I don't want, at least in this
> example.)
> 
> --Mark

• References:
  • Import syntax question
    • From: Mark Fisher <particlefilter@gmail.com>