Many thanks for this. Apologies for incomplete code: Columns=3. Vince On 2 Sep 2011 12:01, "Robert Bradshaw" <rober...@math.washington.edu> wrote: > On Fri, Sep 2, 2011 at 3:44 AM, Vince <vincent.kni...@gmail.com> wrote: >> Dear all, >> >> If I have a list, how do I obtain the cardinality of the list, the >> command Cardinality() doesn't seem to always work. For example, the >> following code produces a set ComSet of sets of combinations. >> >> Rows=3 >> RowVector=[2,3,2] >> ComSet=[] >> for j in range(Columns): >> C=Combinations(range(Rows),RowVector[j]) >> ComSet.append(C.list()) >> show(ComSet) > > What's Columns? > >> However using Cardinality() on ComSet does not seem to work: >> >> ComSet.Cardinality() >> >> Basically I am looking for the mathematica command "Length". > > > FYI, most Python and Sage commands start with a lower case. In this > case, however, what you're looking for is len(ComSet). If you have an > object x, type x-dot-tab to see what methods it supports. > >> Furthermore how would I be able to map that command on to the elements >> of ComSet? > > Use "list comprehensions" (it's a Python thing). > > sage: L = [[1, 2, 3], [4, 5]] > sage: [len(a) for a in L] > [3, 2] > > -- > To post to this group, send email to sage-support@googlegroups.com > To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com > For more options, visit this group at http://groups.google.com/group/sage-support > URL: http://www.sagemath.org
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