Your string
is a single string. It is not a list of strings. You are expecting it to be a list of strings when you are doing this:
for row in string:
When you iterate over a string, you are iterating over its characters. Which is why you are seeing a character per line.
Declare a list of strings. And append every string to it like this:
done = False
strings_list = []
while not done:
string = ""
a = input("Name of player: ")
if a == "":
done = True
else:
string += a + ','
string += input("Age: ") + ','
string += input("Position: ") + '\n'
strings_list.append(string)
Now iterate over this strings_list
and print to the output file. Since you are putting the delimiter (comma) yourself in the string, you do not need a csv writer.
a_file = open(fName, 'w')
for row in strings_list:
print(row)
a_file.write(row)
a_file.close()
Note:
string
is a name of a standard module in Python. It is wise not to use this as a name of any variable in your program. Same goes for your variable file