尝试过滤数组数据时，无法将“String”类型的值转换为预期的参数类型“String.Element”（又名“Character”）

Question

I'm trying to "search" item from an array and if the item contains searchkey, it should appended the data to filteredArray. But when i'm trying to check if the data contains search key it showed an error "Cannot convert value of type 'String' to expected argument type 'String.Element' (aka 'Character')"

Example: let data: [String] = ["Apples", "Apricots", "Bananas", "Cherries", "Grapefruit", "Grapes"] searchKey: "ap" should filter "Apples" and "Appricots". searcKey: "gr" should filter "Grapefruit" and "Grapes".

My code:

let data: [String] = ["Apples", "Apricots", "Bananas", "Cherries", "Grapefruit", "Grapes"]
var filteredData: [String] = []

let searchKey: String = "Ap"

for item in data {
  if item.contains(searchKey) {
    filteredData.append(item)
  }
}

Answer 1

Swift String contains(_:) accepts Character as parameter, instead of String :

func contains(_ element: Character) -> Bool

You can use Generic Instance Method contains(_:) from Foundation :

func contains<T>(_ other: T) -> Bool where T : StringProtocol

Just by importing Foundation and it should work.

Answer 2

Seems your code works properly. You may need to import Foundation. Also, there is a shorter way to filter your data:

let data: [String] = ["Apples", "Apricots", "Bananas", "Cherries", "Grapefruit", "Grapes"]
var filteredData: [String] = []
filteredData = data.filter({ $0.contains("Ap") })