
Re: How do I use Select[list,condition]?
Posted:
Jul 30, 1996 3:02 AM


Jason Welter wrote: > > I have a list that looks like: > > data = {{1,1,a,4,5,6},{2,1,a,2,3,4},{3,1,a,7,8,9}, > {1,2,b,4,5,6},{2,2,b,2,3,4},{3,2,b,7,8,9}, > {1,3,c,4,5,6},{2,3,c,2,3,4},{3,3,c,7,8,9}} > > and I want to pick out the lists that have a 2 as the second element > of the list. I tried something like: > > data1 = Select[data,data[[#,2]]==2]; > > but this doesn't work. How do I do it?
The syntax and use of pure functions in Mathematica took me a while to get used to, but it was (is) well worth the effort. You came close, but forgot some things. It will work if you write it like this:
In[5]:= Select[ data, (#[[2]] == 2)& ] Out[5]= {{1, 2, b, 4, 5, 6}, {2, 2, b, 2, 3, 4}, {3, 2, b, 7, 8, 9}}  _______________________________________________________________ Harald Berndt University of California Research Specialist Forest Products Laboratory Phone: 5102154224 FAX:5102154299 _______________________________________________________________

