如何从字典中打印一些键Swift

Question

I'm experimenting with a little bit of code, this is what I want: I want to print the keys from a dictionary but only if this keys have a value more than 10. This is my code:

var alumnos = ["jose": 20, "leo": 56, "hadad": 8]

In this case only "jose" and "leo" have to be printed, because their values are more than 10.

Answer 1

Have you tried something like this:

for (key, value) in alumnos {
   if value > 10 {
      print(key)
   }
}

You can also turn it into a function like so:

func printKeyForValueGreaterThan10<T: Hashable>(dict: [T: Int]) {
  for (key, value) in dict {
    if value > 10 {
      print(key)
    }
  }
}

And call it by passing your dictionary.

printKeyForValueGreaterThan10(dict: alumnos)

Answer 2

You can obtain the keys of interest using higher-level functions:

let keysOfValuesAboveTen = alumnos.filter {$0.1 > 10}.map {$0.0}

You can make a string with a separator from it like this:

let str = alumnos.filter {$0.1 > 10}.map {$0.0}.joinWithSeparator(", ")

Answer 3

这是解决此问题的最基本方法：

for (stringKey, intValue) in alumnos { if intValue > 10 { print(stringKey) } }