[英]python function for loop in dictonary
我正在嘗試從字典中的特定鍵中檢索所有項目。 該代碼有效,但是我在函數general_info
的輸出中general_info
收到None
語句。 其他功能specific_info
正常工作。 有什么建議嗎? 非常感謝。
countries = {
"canada": {
'name': "Canada",
'location': "North America",
'currency': "Canadian Dollar",
'capital city': "Ottawa",
'population': "32.268.240",
'area': "9.970.610 km2"
},
"brazil": {
'name': "Brazil",
'location': "South America",
'currency': "Brazilian Real",
'capital city': "Brasilia",
'population': "186.404.900",
'area': "8.514.877 km2"
},
"ukraine": {
'name': "Ukraine",
'location': "Europe",
'currency': "Ukrainian Hryvnia",
'capital city': "Kyiv",
'population': "46.480.700",
'area': "603.700 km2"
},
"haiti": {
'name': "Haiti",
'location': "North America",
'currency': "Haitian Gourde",
'capital city': "Port-au-Prince",
'population': "8.527.777",
'area': "27.750 km2"
},
"albania": {
'name': "Albania",
'location': "Europe",
'currency': "Albanian Lek",
'capital city': "Tirana",
'population': "3.129.678",
'area': "28.748 km2"
},
"india": {
'name': "India",
'location': "Asia",
'currency': "Indian Rupee",
'capital city': "New Delhi",
'population': "1.103.371.000",
'area': "3.287.263 km2"
}
}
def general_info(c_name):
for key, val in countries[c_name].items():
info = print(c_name.title() + " " + key + " is " + val)
return info
def specific_info(c_name, info):
if c_name in countries and info in countries[c_name].keys():
return (info.title() + " from " + c_name.title() + " is " + countries[c_name][info])
ask_country = input("Country name: ")
ask_info = input("Information requested: ")
c_name = ask_country.lower()
info = ask_info.lower()
print(general_info(c_name))
print()
print(specific_info(c_name, info))
您將返回打印語句的返回值,該值始終為None。 只需刪除打印件。
下面的代碼中存在多個問題:
def general_info(c_name):
for key, val in countries[c_name].items():
# overwrites info in every iteration
# you are saving return value of print function
info = print(c_name.title() + " " + key + " is " + val)
return info # return only last iteration "info"
def specific_info(c_name, info):
if c_name in countries and info in countries[c_name].keys(): # you can simply write info in countries[c_name]. No need of ".keys()" method
return (info.title() + " from " + c_name.title() + " is " + countries[c_name][info])
要返回一般信息,您應該執行以下操作:
def general_info(c_name):
general_info = []
for key, val in countries[c_name].items():
info = (c_name.title() + " " + key + " is " + val)
general_info.append(info )
return general_info
另外,要格式化字符串,您應該嘗試格式化功能。 我將信息重寫為:
info = "{country}: {key} is {val}".format(country=c_name.title(), key=key, val=val)
這使您的代碼更具可讀性,也易於編寫。
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