how to convert string

[diffuser78 at gmail.com]

I want to print number 0 to 9 in one line like this
0 1 2 3 4 5 6 7 8 9

if I do like this, it prints in different lines

for i in xrange(10):
    print i

so i tried like this

str = ""
for i in xrange(10):
    str = i + " "
print str

but i want to know how convert int i to string.

Every help is appreciate.