Re: need to call data from a list as input but need it in vector form not list form

*To*: mathgroup at smc.vnet.net*Subject*: [mg50680] Re: [mg50648] need to call data from a list as input but need it in vector form not list form*From*: Sseziwa Mukasa <mukasa at jeol.com>*Date*: Fri, 17 Sep 2004 01:15:44 -0400 (EDT)*References*: <200409150550.BAA11792@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

On Sep 15, 2004, at 1:50 AM, T. wrote: > Suppose I have just generated a list named "list" and the output is as > follows. > > {{0.161299}, {0.122965}, {0.055712}, {0.0448334}, {-0.00538706}} > > I want to use this data in the form > > {0.161299, 0.122965, 0.055712, 0.0448334, -0.00538706} > > however i can't call it in with list[[i]] because I just get the > {{},{},{},{}} form with those extra brackets. Use Flatten[list] or list[[All,1]]. > I guess I have a list > and I am trying to convert it to a vector form right? Sorry if my > definitions are confused. One way of specifying your problem is you have a rank 2 list and you want a rank 1 list, or you have a matrix and you want a vector in row (or column in this case they're the same thing) major order. At any rate a list in Mathematica is any expression with the head List, regardless of its structure. What you are concerned about is the structure of a list, in which case you can refer to its rank in the case that it makes sense to think of it as a vector, matrix or other form of tensor. If you don't have a regular structure such a list of the form {{},{{}},{{{}}},{}} then you can refer to its depth or tree form. In either case, Flatten and Partition are usually the functions used to modify a list's structure. Incidentally they work on expressions that don't have the head List. I hope this helps. Regards, Ssezi

**References**:**need to call data from a list as input but need it in vector form not list form***From:*monster_economist@punkass.com (T.)