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RE: Mapping Functions That Take More Than One Argument

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  • Subject: [mg69899] RE: [mg69864] Mapping Functions That Take More Than One Argument
  • From: "David Annetts" <davidannetts at aapt.net.au>
  • Date: Wed, 27 Sep 2006 06:04:01 -0400 (EDT)

Hi Gregory,

> How can I map a functions onto sub-lists when the function 
> takes more than one argument.  I can't seem to stumble upon 
> the right syntax.
> 
> Here's a list of three sub-lists.
> 
> {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}
> 
> I want to drop the first element of each sub-list, that is, 1 
> from the first, 4 from the second, and 7 from the third.
> 
> Drop[{{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}, 1]
> 
> gives me
> 
> {{4, 5, 6}, {7, 8, 9}},
> 
> which is what I expected (I'm learning) but not what I want.  
> So, how do I apply Drop to each sub-list?

There is Map ...

	a = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}
	Drop[#, 1] & /@ a

Running through some of the examples in 2.2.4 might throw some more light on
other applications.

Regards,

Dave


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