如何使用 python 创建 json 对象数组

Question

I have a list of countries and their cities on one website. I take all names of countries and their capitals from this list, and want to put them in JSON file like this:

[
  {
    "country": "Afghanistan",
    "city": "Kabul"
  },
  {
    "country": "Aland Islands",
    "city": "Mariehamn"
  }
]

there's my code:

cells = soup.table('td')
count = 0

cities_list.write('[\n')

for cell in cells:
    if count == len(cells)-2:
        break
    else:
        cities_list.write(json.dumps({"country": "{}".format(cells[count].getText()),
                                      "city": "{}".format(cells[count].next_sibling.getText())},
                                       indent=2))
    count += 2

cities.list_write('\n]')

And my problem is that objects are not separated by comma:

[
{
  "country": "Afghanistan",
  "city": "Kabul"
}{
  "country": "Aland Islands",
  "city": "Mariehamn"
}
]

How can I make my objects separated by comma, and also is it possible to do without writing '\n]' at the end and beginning?

Answer 1

Python obviously has no way to know that you are writing a list of objects when you are writing them one at a time... so just don't.

cells = soup.table('td')

cities = []
for cell in cells[:-2]:
    cities.append({"country": str(cells[count].getText()),
                   "city": str(cells[count].next_sibling.getText())})

json.dump(cities, cities_list)

Notice also how "{}".format(value) is just a clumsy way to write str(value) (or just value if value is already a string) and how json.dump lets you pass an open file handle to write to.