将带有元祖的列表变成字典/字典key与value位置调换

将带有元祖的列表变成字典：

dial_codes =[
    (86,'China'),
    (81,'Japan'),
    (1,'United States'),
    (7,'Russia'),
    (880,'Bangladesh'),   
    ]

country_code = {country: code for code , country in dial_codes}
print(country_code)

#output:{'China': 86, 'Japan': 81, 'United States': 1, 'Russia': 7, 'Bangladesh': 880}

将key, value(无重复) 对换：

{code:country.upper() for country, code in country_code.items() if code <66}
#output: {1: 'UNITED STATES', 7: 'RUSSIA'}