[Tutor] How parse files in function of number of lines

[jarod_v6 at libero.it]

Dear all!
I have two example files:
tmp.csv:
name	value	root
mark	34	yes

tmp2.csv
name	value	root


I want to print a different text if I have more than one row and if I have 
only one row. My code is this:
with open("tmp.csv") as p:
    header =p.next()
    for i in p:
        print i
        g = ()
    if not g:
            print  header
mark	34	yes

no

I want to obtain only where I have only the header the header string? How can 
I do this?Thnks for your great patience and help!