Re: list referencing with [[ ]][[ ]]
- To: mathgroup at smc.vnet.net
- Subject: [mg13991] Re: [mg13969] list referencing with [[ ]][[ ]]
- From: Xah Lee <xah at best.com>
- Date: Sat, 12 Sep 1998 16:59:15 -0400
- Sender: owner-wri-mathgroup at wolfram.com
At 7:06 PM -0000 1998.09.11, Tim Dellinger wrote: >According to "the book" section 1.8.4, > >t[][] "is equivalent to" t[[1,2]], "but is clumsier to write" >... > >But... The answer can be found by looking at FullForm, In:= FullForm[Hold[li[][]]] Out//FullForm= Hold[Part[Part[li,1],2]] In:= FullForm[Hold[li[[1,2]]]] Out//FullForm= Hold[Part[li,1,2]] Both forms acts equivalently when you use them to extract an element, but for assignment, Part[Part[li,1],2]=x is not the same as Part[li,1,2]=x. Xah, xah at best.com http://www.best.com/~xah/PageTwo_dir/more.html Perl: all unix's stupidity in one.