import re
pattern = r"\b([A-Za-z]+/),(?:\d+,\d+%)+"
itemsales = "Apple/,20,3%20,3%20,3%20,3,"
sales_fixed = re.sub(
pattern,
lambda x: x.group().replace('%', ",{0},".format(x.group(1))),
itemsales
)
print(sales_fixed)
aW1wb3J0IHJlCgpwYXR0ZXJuID0gciJcYihbQS1aYS16XSsvKSwoPzpcZCssXGQrJSkrIgppdGVtc2FsZXMgPSAiQXBwbGUvLDIwLDMlMjAsMyUyMCwzJTIwLDMsIgoKc2FsZXNfZml4ZWQgPSByZS5zdWIoCiAgICBwYXR0ZXJuLAogICAgbGFtYmRhIHg6IHguZ3JvdXAoKS5yZXBsYWNlKCclJywgIix7MH0sIi5mb3JtYXQoeC5ncm91cCgxKSkpLAogICAgaXRlbXNhbGVzCikKCnByaW50KHNhbGVzX2ZpeGVkKQ==
Apple/,20,3,Apple/,20,3,Apple/,20,3,Apple/,20,3,