Re: newbie list question

*To*: mathgroup at smc.vnet.net*Subject*: [mg114988] Re: newbie list question*From*: Patrick Scheibe <pscheibe at trm.uni-leipzig.de>*Date*: Tue, 28 Dec 2010 06:46:21 -0500 (EST)

Hi, the long and readable version is listA = {4, 5, 8, 2, 6, 4}; listB = {8, 4, 2}; Function[{searchItem}, First[Position[listA, searchItem]]] /@ listB but there's no need to use the verbose form of Function: In[13]:= listA = {4, 5, 8, 2, 6, 4}; listB = {8, 4, 2}; First@Position[listA, #] & /@ listB Out[15]= {{3}, {1}, {4}} If you don't like that Position gives a list of possible positions of each element you can use Flatten to flatten out the list. Cheers Patrick On Sun, 2010-12-26 at 04:02 -0500, Gareth Edwards wrote: > Hi, > > Liking Mathematica a lot, but struggling with the early part of the learning curve, i.e. don't know what I don't know... > > What would be the neatest syntax for finding the first location of elements from one list in another? For example: > > listA = { 4,5,8,2,6,4 } > listB = { 8,4,2 } > > > I would like a function to return {3,1,4} in this case (the first location in A of each element in B) > > Many thanks! >