Part // interesting undocumented feature

*To*: mathgroup at smc.vnet.net*Subject*: [mg122669] Part // interesting undocumented feature*From*: "Scot T. Martin" <smartin at seas.harvard.edu>*Date*: Sat, 5 Nov 2011 04:47:16 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

A colleague new to Mathematica showed me something that I thought should cause an error: Part[data[[All,1]]] Of course, I thought the form should just be "data[[All,1]". It turns out that there is form of Part that works like an identity function: In[1]:= Part[5] Out[1]= 5 Just out of a Mathematica trivia challenge question, can anyone think of an example when this undocumented syntax of Part[ ] could possibly be of use or why the programmers have it as an acceptable syntax?