One way

hirnyk — Mon, 06 Jun 2011 21:04:23 Z

It can be done in such a way (This way is not shortest, but it is simple.):
> f := x^2*y+3*x*y^2+x^3*y^3-x^5+y^4*z^5:
>a:= select(has, f, x);#we select all monoms of f with x
x^2*y+3*x*y^2+x^3*y^3-x^5
>degree(a) # the total degree of a
6

Of course, we can combine these:

>degree(select(has, f, x));

Look at ?select and ?degree.

Another way

Alec Mihailovs — Mon, 06 Jun 2011 23:54:08 Z

In addition to the way suggested by Markiyan Hirnyk, that could be done also as

degree(f-eval(f,x=0));

                                  6

The usage is approximately the same,

p:=expand(randpoly(x,dense,degree=1000,coeffs=(()->randpoly(y,dense,degree=2000)))+
randpoly(y,dense,degree=1000,coeffs=(()->randpoly(z,dense,degree=2000)))):

CodeTools:-Usage(degree(p-eval(p,x=0)));
memory used=121.58MiB, alloc change=121.60MiB, cpu time=7.50s, real time=7.64s

                                 3000

CodeTools:-Usage(degree(select(has, p, z)));
memory used=218.90MiB, alloc change=128.04MiB, cpu time=7.38s, real time=7.44s

                                 3000

Alec

MaplePrimes - answers and comments on Question, Total degree in which a variable appears

One way

Another way