Swift: Get all key value pairs from a String

Question

I have a String which has many key value pairs appended by a & sign. i.e: params = key1=Hello&key2=Hello World&key3=Hi Hello

Is there a way to extract the values just by passing the keys present in the string? For example I want to extract the value of key1, key2, key3.

If the *string* is part of an URL take a look at `URLComponents` and `URLQueryItem` — vadian, Aug 17 '17 at 07:58
No, It is not a part of an URL. I am receiving an encoded string with just the parameters. After decoding it, I am getting the above string. — JMS, Aug 17 '17 at 08:00
just use [yourString componentSeoratedByString:@"&"]; You will find an array. Now manipulate your array. — Gagan_iOS, Aug 17 '17 at 08:08

score 3 · Answer 1 · edited Feb 02 '20 at 10:44

3

let string = "key1=Hello&key2=Hello World&key3=Hi Hello"

let components = string.components(separatedBy: "&")


var dictionary: [String : String] = [:]

for component in components{
  let pair = component.components(separatedBy: "=")
  dictionary[pair[0]] = pair[1]
}

And in dictionary you will get your key-value pairs.

edited Feb 02 '20 at 10:44

Joannes

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answered Aug 17 '17 at 08:02

Juri Noga

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vadian · Accepted Answer · 2017-08-17T08:19:38.720

1

You can use URLComponents and URLQueryItem anyway by creating a dummy URL

let params = "key1=Hello&key2=Hello World&key3=Hi Hello"
if let components = URLComponents(string: "http://dummy.com/path?" + params.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed)!),
    let queryItems = components.queryItems {
    let arrayOfValues = queryItems.flatMap{ $0.value }
    print(arrayOfValues)
}

see also Best way to parse URL string to get values for keys?

edited Aug 17 '17 at 08:19

answered Aug 17 '17 at 08:12

vadian

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1

Thank you. I tried it and got the required results. – JMS Aug 17 '17 at 08:37

Durdu · Answer 3 · 2017-08-17T10:41:06.493

0

let params = "key1=Hello&key2=Hello World&key3=Hi Hello"

let sepparated = params.components(separatedBy: CharacterSet(charactersIn: "&="))
let keys = sepparated.enumerated().filter{$0.0 % 2 == 0}
print (keys) // [(offset: 0, element: "key1"), (offset: 2, element: "key2"), (offset: 4, element: "key3")]

edited Aug 17 '17 at 10:41

answered Aug 17 '17 at 08:12

Durdu

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`index(of:)` is not sufficient because a value which is equal to a later occurring key would break the code. Just use `let keys = separated.enumerated().filter{$0.0 % 2 == 0}` instead, which would also run in O(n) instead of O(n^2). – Palle Aug 17 '17 at 09:05

Swift: Get all key value pairs from a String

3 Answers3