import json
filename = 'population.json'
with open(filename) as f:
pop_data = json.load(f)
for pop_dict in pop_data:
if pop_dict["Year"] == "1960":
country_name = pop_dict["Country Name"]
population = pop_dict["Value"]
print(country_name+': '+population)
运行后为什么没有打印出任何东西???