Codable: Can't Parse JSON File Swift Xcode 12

Question

tmsm1999 OP

Created Oct ’20

Replies 1

Boosts 0

Views 3.5k

Participants 2

Hello everybody,

I am trying to parse a JSON file that has this structure:

Code Block {
    "species":[
        {
            "name":"Aglais io",
            "info": {
                "family":"Nymphalidae",
                "iNatLink":"https://www.inaturalist.org/observations?place_id=any&taxon_id=207977",
                "WikipediaLink":"https://en.wikipedia.org/wiki/Aglais_io",
                "otherName":"European Peacock Butterfly"
            }
        },
        {
            "name":"Aglais urticae",
            "info": {
                "family":"Nymphalidae",
                "iNatLink":"https://www.inaturalist.org/observations?place_id=any&taxon_id=54468",
                "WikipediaLink":"https://en.wikipedia.org/wiki/Small_tortoiseshell",
                "otherName":"Small Tortoiseshell"
            }
        }
    ]
}

I am using a Codable struct to read the data.
Also, I am using this code to read the json file.

Code Block struct Species: Codable {
    
    let name: String
    
    struct info: Codable {
        let family: String
        let iNatLink: String
        let WikipediaLink: String
        let otherName: String
    }
}
func loadSpeciesInfoJSOn() {
    
    if let filePath = Bundle.main.url(forResource: "secondJSON", withExtension: "json") {
        
        do {
            let data = try Data(contentsOf: filePath)
            let decoder = JSONDecoder()
            let speciesList = try decoder.decode([Species].self, from: data)
            
            print(speciesList)
        } catch {
            print("Can not load JSON file.")
        }
    }
}

I can not figure out what I am doing wrong.

Thank you for your help.

Answered by OOPer in 640352022

Your JSON text is outlined as :

Code Block {
    "species": [
        ...
    ]
}

The outermost structure of it is JSON object with a single entry with the key "species" and the value is a JSON array.

You need a Codable struct with an entry species. (And a little bit fix in Species.)

Code Block struct SpeciesInfo: Codable {
    let species: [Species]
}
struct Species: Codable {
    
    let name: String
    
    let info: Info //<-
    
    struct Info: Codable { //<-
        let family: String
        let iNatLink: String
        let WikipediaLink: String
        let otherName: String
    }
}

Use the above struct as:

Code Block             let decoder = JSONDecoder()
            let speciesInfo = try decoder.decode(SpeciesInfo.self, from: data)
            let speciesList = speciesInfo.species
            print(speciesList)

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Answer 1

OOPer OP

Oct ’20

Accepted Answer

Your JSON text is outlined as :

Code Block {
    "species": [
        ...
    ]
}

The outermost structure of it is JSON object with a single entry with the key "species" and the value is a JSON array.

You need a Codable struct with an entry species. (And a little bit fix in Species.)

Code Block struct SpeciesInfo: Codable {
    let species: [Species]
}
struct Species: Codable {
    
    let name: String
    
    let info: Info //<-
    
    struct Info: Codable { //<-
        let family: String
        let iNatLink: String
        let WikipediaLink: String
        let otherName: String
    }
}

Use the above struct as:

Code Block             let decoder = JSONDecoder()
            let speciesInfo = try decoder.decode(SpeciesInfo.self, from: data)
            let speciesList = speciesInfo.species
            print(speciesList)

1