如何在Swift中编辑字典中的值

Question

var airports : [String:String] = ["DXB" : "dubai international airport", "LHR" : "heathrow international airport"]

for (airportCode,airportName) in airports
{
airportName = airportName.capitalized
}

所以我需要大写所有值，但是我得到了错误

“无法分配给值：airportName是一个让常量

Answer 1

只需在您的for循环中添加var

var airports : [String:String] = ["DXB" : "dubai international airport", "LHR" : "heathrow international airport"]

for (var airportCode,var airportName) in airports
{
airportName = airportName.capitalized
airports[airportCode] = airportName
}

Answer 2

根据定义，索引变量是常量。 你可以做

var airports = ["DXB" : "dubai international airport", "LHR" : "heathrow international airport"]
for (airportCode, airportName) in airports
{
    airports[airportCode] = airportName.capitalized
}

Answer 3

这可能不是最好的解决方案，但是它很有效而且很简单：

let keys = airports.keys
for key in keys {
    airports[key] = airports[key]!.capitalized
}

首先，获得字典中的所有键，并为每个键设置相应的值。