-----maxima-bounces at math.utexas.edu wrote: ----- >There may be simpler ways, if maxima implemented "push" or for that matter, "filter". For push and pop macros, load "basic": (%i1) load(basic)$ (%i2) l : []$ (%i3) push(x,l); (%o3) [x] (%i4) l; (%o4) [x] (%i5) pop(l); (%o5) x (%i6) l; (%o6) [] BW