Re: Q: Extract Elements from a List?
- To: mathgroup at smc.vnet.net
- Subject: [mg28987] Re: [mg28968] Q: Extract Elements from a List?
- From: Al Kaufman <nutronstar at rickadee.net>
- Date: Thu, 24 May 2001 04:07:04 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
>hi!
>
>probably a very easy question, but i couldn't find an answer in the
>mathematica-book:
>
>i need to extract elements from a list, starting th element number x and
>than taking every yth element, eg:
>
>with
>
>lst={a,b,c,d,e,f,g,h,i,j}
>start=3;
>step=2;
>
>i'd like to get the list
>
>{c,e,g,i}.
>
>how can i do this in the easiest way?
>
>regards, robert
The solution is straight forward. Use the Part function as the selector:
In[1]:=
lst = {a, b, c, d, e, f, g, h, i, j};
start = 3;
step = 2;
xtr = Part[lst,Table[p,{p,start,Length[lst],step}]];
In[2]:=
xtr
Out[2]:=
{c,e,g,i}
Good luck
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