How to Custom Decode each element of an array using Swift Decodable
I am decoding a weather JSON response, and I want to pass information to a child decoder which will be decoding an array. How can I pass in this information for every JSON array element while decoding with Swift Decodable?
I am trying to do the above in the latest Swift version (4.2), and I've already implemented the necessary code to successfully custom decode the same model as is being used in the array. I have been unable to decode the entire array.
struct DataBlock: Decodable {
/..
let weather: [DataPoint]?
init(from decoder: Decoder) throws {
try self.init(from: decoder, units: .unit)
}
init(from decoder: Decoder, units: Units) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
/..
let nestedDecoder = try values.superDecoder(forKey: .weather)
self.weather = try [DataPoint(from: nestedDecoder, units: units)]
}
enum CodingKeys: String, CodingKey {
/..
case weather
}
}
And in the DataPoint model:
init(from decoder: Decoder, units: Units) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
/...
if let value = try values.decodeIfPresent(Double.self, forKey: .value) {
self.value = Example(value: value, units: units)
} else {
self.value = nil
}
/..
}
The relevant part of the JSON structure I am trying to decode:
"datablock": {
"weather": [
{
/..
"value": 22.72
/..
}
]
}
I expect the decoder to pass in
units
and decode each array element manually.
However I get a debug error:
"Expected to decode Dictionary<String, Any> but found an array instead."
The error gets triggered here:
self.weather = try [DataPoint(from: nestedDecoder, units: units)]
arrays swift decodable
asked Jan 3 at 0:10
JackFrostJackFrost
14
add a comment |
I am decoding a weather JSON response, and I want to pass information to a child decoder which will be decoding an array. How can I pass in this information for every JSON array element while decoding with Swift Decodable?
I am trying to do the above in the latest Swift version (4.2), and I've already implemented the necessary code to successfully custom decode the same model as is being used in the array. I have been unable to decode the entire array.
struct DataBlock: Decodable {
/..
let weather: [DataPoint]?
init(from decoder: Decoder) throws {
try self.init(from: decoder, units: .unit)
}
init(from decoder: Decoder, units: Units) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
/..
let nestedDecoder = try values.superDecoder(forKey: .weather)
self.weather = try [DataPoint(from: nestedDecoder, units: units)]
}
enum CodingKeys: String, CodingKey {
/..
case weather
}
}
And in the DataPoint model:
init(from decoder: Decoder, units: Units) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
/...
if let value = try values.decodeIfPresent(Double.self, forKey: .value) {
self.value = Example(value: value, units: units)
} else {
self.value = nil
}
/..
}
The relevant part of the JSON structure I am trying to decode:
"datablock": {
"weather": [
{
/..
"value": 22.72
/..
}
]
}
I expect the decoder to pass in
units
and decode each array element manually.
However I get a debug error:
"Expected to decode Dictionary<String, Any> but found an array instead."
The error gets triggered here:
self.weather = try [DataPoint(from: nestedDecoder, units: units)]
arrays swift decodable
asked Jan 3 at 0:10
JackFrostJackFrost
14
Can you show the JSON you are trying to decode?
– Sweeper
Jan 3 at 0:13
Whoops, I just added the JSON section!
– JackFrost
Jan 3 at 1:05
And where is that error being thrown?
– Frakcool
Jan 3 at 1:30
Can you post the url you are using to fetch the JSON response? or a link to a file with the json data received?
– Leo Dabus
Jan 3 at 2:01
Clarified the line where the error is being thrown
– JackFrost
Jan 3 at 3:20
add a comment |
I am decoding a weather JSON response, and I want to pass information to a child decoder which will be decoding an array. How can I pass in this information for every JSON array element while decoding with Swift Decodable?
I am trying to do the above in the latest Swift version (4.2), and I've already implemented the necessary code to successfully custom decode the same model as is being used in the array. I have been unable to decode the entire array.
struct DataBlock: Decodable {
/..
let weather: [DataPoint]?
init(from decoder: Decoder) throws {
try self.init(from: decoder, units: .unit)
}
init(from decoder: Decoder, units: Units) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
/..
let nestedDecoder = try values.superDecoder(forKey: .weather)
self.weather = try [DataPoint(from: nestedDecoder, units: units)]
}
enum CodingKeys: String, CodingKey {
/..
case weather
}
}
And in the DataPoint model:
init(from decoder: Decoder, units: Units) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
/...
if let value = try values.decodeIfPresent(Double.self, forKey: .value) {
self.value = Example(value: value, units: units)
} else {
self.value = nil
}
/..
}
The relevant part of the JSON structure I am trying to decode:
"datablock": {
"weather": [
{
/..
"value": 22.72
/..
}
]
}
I expect the decoder to pass in
units
and decode each array element manually.
However I get a debug error:
"Expected to decode Dictionary<String, Any> but found an array instead."
The error gets triggered here:
self.weather = try [DataPoint(from: nestedDecoder, units: units)]
arrays swift decodable
asked Jan 3 at 0:10
JackFrostJackFrost
14
I am decoding a weather JSON response, and I want to pass information to a child decoder which will be decoding an array. How can I pass in this information for every JSON array element while decoding with Swift Decodable?
I am trying to do the above in the latest Swift version (4.2), and I've already implemented the necessary code to successfully custom decode the same model as is being used in the array. I have been unable to decode the entire array.
struct DataBlock: Decodable {
/..
let weather: [DataPoint]?
init(from decoder: Decoder) throws {
try self.init(from: decoder, units: .unit)
}
init(from decoder: Decoder, units: Units) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
/..
let nestedDecoder = try values.superDecoder(forKey: .weather)
self.weather = try [DataPoint(from: nestedDecoder, units: units)]
}
enum CodingKeys: String, CodingKey {
/..
case weather
}
}
And in the DataPoint model:
init(from decoder: Decoder, units: Units) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
/...
if let value = try values.decodeIfPresent(Double.self, forKey: .value) {
self.value = Example(value: value, units: units)
} else {
self.value = nil
}
/..
}
The relevant part of the JSON structure I am trying to decode:
"datablock": {
"weather": [
{
/..
"value": 22.72
/..
}
]
}
I expect the decoder to pass in
units
and decode each array element manually.
However I get a debug error:
"Expected to decode Dictionary<String, Any> but found an array instead."
The error gets triggered here:
self.weather = try [DataPoint(from: nestedDecoder, units: units)]
arrays swift decodable
arrays swift decodable
asked Jan 3 at 0:10
JackFrostJackFrost
14
asked Jan 3 at 0:10
JackFrostJackFrost
14
edited Jan 3 at 2:47
JackFrost
asked Jan 3 at 0:10
JackFrostJackFrost
14
asked Jan 3 at 0:10
JackFrostJackFrost
14
asked Jan 3 at 0:10
JackFrostJackFrost
14
14
Can you show the JSON you are trying to decode?
– Sweeper
Jan 3 at 0:13
Whoops, I just added the JSON section!
– JackFrost
Jan 3 at 1:05
And where is that error being thrown?
– Frakcool
Jan 3 at 1:30
Can you post the url you are using to fetch the JSON response? or a link to a file with the json data received?
– Leo Dabus
Jan 3 at 2:01
Clarified the line where the error is being thrown
– JackFrost
Jan 3 at 3:20
add a comment |
Can you show the JSON you are trying to decode?
– Sweeper
Jan 3 at 0:13
Whoops, I just added the JSON section!
– JackFrost
Jan 3 at 1:05
And where is that error being thrown?
– Frakcool
Jan 3 at 1:30
Can you post the url you are using to fetch the JSON response? or a link to a file with the json data received?
– Leo Dabus
Jan 3 at 2:01
Clarified the line where the error is being thrown
– JackFrost
Jan 3 at 3:20
Can you show the JSON you are trying to decode?
– Sweeper
Jan 3 at 0:13
Can you show the JSON you are trying to decode?
– Sweeper
Jan 3 at 0:13
Whoops, I just added the JSON section!
– JackFrost
Jan 3 at 1:05
Whoops, I just added the JSON section!
– JackFrost
Jan 3 at 1:05
And where is that error being thrown?
– Frakcool
Jan 3 at 1:30
And where is that error being thrown?
– Frakcool
Jan 3 at 1:30
Can you post the url you are using to fetch the JSON response? or a link to a file with the json data received?
– Leo Dabus
Jan 3 at 2:01
Can you post the url you are using to fetch the JSON response? or a link to a file with the json data received?
– Leo Dabus
Jan 3 at 2:01
Clarified the line where the error is being thrown
– JackFrost
Jan 3 at 3:20
Clarified the line where the error is being thrown
– JackFrost
Jan 3 at 3:20
add a comment |
1 Answer
1
active
oldest
votes
This solves my issue by letting me 'walkthrough' each JSON array element and decode each separately:
struct DataBlock: Decodable {
/..
init(from decoder: Decoder, units: Units) throws {
/..
var data = [DataPoint]()
var dataContainer = try values.nestedUnkeyedContainer(forKey: .data)
while !dataContainer.isAtEnd {
let nestedDecoder = try dataContainer.superDecoder()
let dataPoint = try DataPoint(from: nestedDecoder, units: units)
data.append(dataPoint)
}
self.data = data
/..
}
/..
}
answered Jan 3 at 21:55
JackFrostJackFrost
14
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
This solves my issue by letting me 'walkthrough' each JSON array element and decode each separately:
struct DataBlock: Decodable {
/..
init(from decoder: Decoder, units: Units) throws {
/..
var data = [DataPoint]()
var dataContainer = try values.nestedUnkeyedContainer(forKey: .data)
while !dataContainer.isAtEnd {
let nestedDecoder = try dataContainer.superDecoder()
let dataPoint = try DataPoint(from: nestedDecoder, units: units)
data.append(dataPoint)
}
self.data = data
/..
}
/..
}
answered Jan 3 at 21:55
JackFrostJackFrost
14
add a comment |
This solves my issue by letting me 'walkthrough' each JSON array element and decode each separately:
struct DataBlock: Decodable {
/..
init(from decoder: Decoder, units: Units) throws {
/..
var data = [DataPoint]()
var dataContainer = try values.nestedUnkeyedContainer(forKey: .data)
while !dataContainer.isAtEnd {
let nestedDecoder = try dataContainer.superDecoder()
let dataPoint = try DataPoint(from: nestedDecoder, units: units)
data.append(dataPoint)
}
self.data = data
/..
}
/..
}
answered Jan 3 at 21:55
JackFrostJackFrost
14
add a comment |
This solves my issue by letting me 'walkthrough' each JSON array element and decode each separately:
struct DataBlock: Decodable {
/..
init(from decoder: Decoder, units: Units) throws {
/..
var data = [DataPoint]()
var dataContainer = try values.nestedUnkeyedContainer(forKey: .data)
while !dataContainer.isAtEnd {
let nestedDecoder = try dataContainer.superDecoder()
let dataPoint = try DataPoint(from: nestedDecoder, units: units)
data.append(dataPoint)
}
self.data = data
/..
}
/..
}
answered Jan 3 at 21:55
JackFrostJackFrost
14
This solves my issue by letting me 'walkthrough' each JSON array element and decode each separately:
struct DataBlock: Decodable {
/..
init(from decoder: Decoder, units: Units) throws {
/..
var data = [DataPoint]()
var dataContainer = try values.nestedUnkeyedContainer(forKey: .data)
while !dataContainer.isAtEnd {
let nestedDecoder = try dataContainer.superDecoder()
let dataPoint = try DataPoint(from: nestedDecoder, units: units)
data.append(dataPoint)
}
self.data = data
/..
}
/..
}
answered Jan 3 at 21:55
JackFrostJackFrost
14
answered Jan 3 at 21:55
JackFrostJackFrost
14
answered Jan 3 at 21:55
JackFrostJackFrost
14
answered Jan 3 at 21:55
JackFrostJackFrost
14
14
add a comment |
add a comment |
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Can you show the JSON you are trying to decode?
– Sweeper
Jan 3 at 0:13
Whoops, I just added the JSON section!
– JackFrost
Jan 3 at 1:05
And where is that error being thrown?
– Frakcool
Jan 3 at 1:30
Can you post the url you are using to fetch the JSON response? or a link to a file with the json data received?
– Leo Dabus
Jan 3 at 2:01
Clarified the line where the error is being thrown
– JackFrost
Jan 3 at 3:20