Re: Another question on lists

*To*: mathgroup at smc.vnet.net*Subject*: [mg80671] Re: Another question on lists*From*: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>*Date*: Tue, 28 Aug 2007 02:19:21 -0400 (EDT)*Organization*: The Open University, Milton Keynes, UK*References*: <fatglk$2k6$1@smc.vnet.net>

Mauricio Esteban Cuak wrote: > Hello again.Thank you very much for your previous help. However, I > seem to stumble on another rock: > > I have a list of n sub-lists with different number of elements. I > want to select the list with the highest number of elements. > I tried to combine the Select function with Lenght but couldn't do it: > > Select[list, Length /@ list >= Max[Length /@ list] &] You were almost there: you must take the length of the current element (i.e. Length[#]) and compare it against the greatest length of of every element (Length /@ lst). For instance, In[1]:= lst = {{1, 2, 3, 4}, {5, 6}, {7, 8, 9, 10}, {11, 12, 13}}; Select[lst, Length[#] == Max[Length /@ lst] & ] Out[2]= {{1, 2, 3, 4}, {7, 8, 9, 10}} <snip> > P.D.: Any tips,websites, books, on how to learn some basic programming > on Mathematica? > I'm slowly beginning to read "The Mathematica Book"...should I just > concentrate on that? An excellent book to start learning programming Mathematica is, _An Introduction to Programming with Mathematica_, 3rd Edition, Paul R. Wellin, Richard J. Gaylord, and Samuel N. Kamin, Cambridge University Press, (ISBN-13: 9780521846783 | ISBN-10: 0521846781). See http://www.cambridge.org/catalogue/catalogue.asp?isbn=9780521846783 Table of Contents: 1. An introduction to Mathematica; 2. The Mathematica language; 3. Lists; 4. Functional programming; 5. Procedural programming; 6. Rule-based programming; 7. Recursion; 8. Numerics; 9. Graphics programming; 10. Front-end programming; 11. Examples and applications; 12. Writing packages; Appendix A: how expressions are evaluated; Appendix B: debugging. (Notebooks, code examples and solutions to some exercises, are available on the publisher web site. See the above link.) About free resources, a good start would be to search MathSource (part of the Wolfram Library Archive) For instance, _Programming Paradigms via Mathematica (A First Course)_ may be of interest. See http://library.wolfram.com/infocenter/MathSource/1847/ Hope this helps, -- Jean-Marc