Python - What's the error in this code?

Question

Why list is not joined?
Compiler tells me something as "string expected, int found"

def func(x):
for i in range(x):
yield i**2
print(",".join(list(func(3))))

Answer 1

It's because you can't join a list of integers. The elements of the list have to be a string. Here is a fix:

print(",".join([str(i) for i in func(3)]))

Answer 2

or
yield str(i**2)