I have a struct and an array of my structs as follows
struct Products{
var ProductType: String
var ProductName: String
var ProductLink: String
}
var CleaningProductsArray = [Products]()
When I write to my array of structs the ProductName Variable inside it sometimes can be written by the user with trailing whitespaces. I would like to return a version of the CleaningProductsArray but with all instances of ProductName having any trailing whitespaces removed. I have been trying to achieve with map as below but does not return what I would like it to. What is the most efficient way to do this?
let trimmed = CleaningProductsArray.map{ $0.ProductName.trimmingCharacters(in: .whitespaces) }
Quick answer is:
let trimmed: [Products] = CleaningProductsArray.map { product in
var adjusted = product
adjusted.ProductName = product.ProductName.trimmingCharacters(in: .whitespaces)
return adjusted
}
As it was correctly mentioned in the comments, there are things you can improve in your overall code design.
You could start with converting your model to meet Swift naming standards, which means not using plural for Products since the objects of this type describe a single product, and removing the product prefix from properties since its obvious from the context that they describe a "Product". Ideally you would also make the properties immutable, to make passing them around safer (google "Benefits of immutability"). You should create some other object responsible for collecting all the data for your product objects.
struct Product {
let type: String
let name: String
let link: String
}
Also, you should never use uppercased names for your variables/constants/properties/functions in Swift, so it's best to replace the CleaningProductsArray with cleaningProductsArray for the sake of readability. Uppercased names are reserved for types. Also you might want to drop the Array suffix since it's obvious from the type that it is an array
var cleaningProducts = [Product]()
let trimmed: [Product] = cleaningProducts.map {
Product(
type: $0.type,
name: $0.name.trimmingCharacters(in: .whitespaces),
link: $0.link
)
}
Related
There are two simple problems here in initializing this structure.
One is the enunumerated value TS (I get error : Cannot convert value of type 'TournNames' to expected argument type 'TournamentName')
the other is initializing an array of strings (I get the error : Cannot convert value of type '[String]' to expected argument type 'TouramentScores'
Suppose I am trying to set up a structure to model the scores of tennis players and all of their matches in each of the major tournaments (just for fun). Each tournament has a name (e.g. Wimbledon) and a series of scores for that player (for example, in the opening match, their score might be "4-6, 6-4, 7-6, 6-2")... upto 7 matches in each tournament. Each player should have an array of four tournaments (names and array of scores), and eventually there should be an array of players. I am also trying to use enums not too successfully. Ideally, if I want to find how Roger Federer did in his third match of wimbledon this year, I would access something like player.tournament.wim.Roundof32 or something roughly like that. But before I can even get to playing with that, I can't seem to init dummy data for even a single tournament.
Any ideas? I don't think this is that hard of question but I just don't know each. See "*** this line" below for two lines that are problematic
// tournament name enum
enum TournNames : String {
case wim = "Wimbledom"
case fo = "French Open"
case ao = "Australian Open"
case uo = "US Open"
}
//
struct TournamentName {
var Tname : TournNames // = .wim
}
// This is the structure for a tournament score array with some dummy values.
struct TouramentScores {
var Match1 : String = "7-6, 6-4, 3-6, 7-6"
var Match2 : String = "7-6, 6-4, 3-6, 7-6"
}
// This is one entire Tournament record for one player = tournament name + array of scores ... the next goal but not used here until I get over these hurdles
struct TournamentResult {
var TournamentName : TournNames = .wim
var Scores : TouramentScores
}
// ... finally the structure of a player ...
struct DummyTennisPlayer {
var LastName : String // last name
var FirstName : String //first name
var TN : TournamentName
var TS : TouramentScores
// var WimRes : TournamentResult // to start a single tournament
// var SeasonResults : [TournamentResult] // ultimately should be an array of 4 tournaments
}
// trying to initialize some dummy data without success after trying several things
extension DummyTennisPlayer {
static var dummyResults : [DummyTennisPlayer] {
[
DummyTennisPlayer.init(
LastName : "Federer",
FirstName: "Roger",
TN : TournNames.wim // **** this line
,
TS : ["XX", "yy"] /// *** this line
)
]
}
}
As I think you're discovering, a simple series of nested types is unlikely to cut it here. As soon as you get to entities like players, tournaments, matches and lookups like "how Roger Federer did in his third match of wimbledon this year", you've become a candidate for using a database where you can manipulate one-to-many and many-to-many relationships. I can't tell you what database to use, and anyway that's a matter of opinion; from what you've said so far, SQLite would be sufficient (and I am personally not a fan of Core Data just for this kind of thing).
I guess your code is a kind of exercise, so before you go on later to Core Data or SQLite,
extension DummyTennisPlayer {
static var dummyResults: [DummyTennisPlayer] = [
DummyTennisPlayer(LastName: "Federer", FirstName: "Roger", WimbledomResult: TournamentResult(Scores: TouramentScores()))
]
}
should answer your question.
1 - To initialize a Swift struct, use the following syntax:
MyStruct(property1: "my property1 value", property2: "my property2 value")
2 - the tournament name property in TournamentResult is already set to .wim so you just need to initialize the Scores. As your TournamentScores properties are already all set, you just need to pass an instance of TournamentScores() to TournamentResult(Scores:).
By the way, only use lowercases for the first letter of the name of your variables or struct properties: var lastName or TournamentResult(scores:).
I think you are confusing the term "multi-dimensional (array) structures" (which are just arrays nested inside other arrays, like that: [ [1, 2, 3], [2, 3, 4], [3, 4, 5]]) with the struct objects. You are probably not supposed to use structs so extensively here.
Don't hesitate to review the way you decide to use enums, structs, or arrays. Your code may work but will be difficult to read and use (example: how would you access a specific set score if you put all of the set scores in a single String? Why not use an array?)
I'm trying to filter a set of objects based on values in one of their elements based on another array. I've got it working with filter just fine if the search is "OR" - it returns give me all objects for which at least one of the strings in the search array is found.
But I can't figure out how to make it work as an AND search - returning only the objects that match ALL of the strings in the search array.
Example:
struct Schedule {
let title: String
let classTypes: [String]
}
let schedule1 = Schedule(title: "One", classTypes: ["math","english","chemistry","drama"])
let schedule2 = Schedule(title: "Two", classTypes: ["pe","math","biology"])
let schedule3 = Schedule(title: "Three", classTypes: ["english","history","math","art"])
let schedules = [schedule1, schedule2, schedule3]
let searchArray = ["math", "english"]
//works for OR - "math" or "english"
var filteredSchedules = schedules.filter { $0.classTypes.contains(where: { searchArray.contains($0) }) }
I'd like to find a way for it to use the same search array
let searchArray = ["math", "english"]
But only return items 1 & 3 - as they both have BOTH math and english in the list.
There are good examples of AND conditions when the AND is across different search criteria: car type and colour - but I've been unable to find an example where the criteria are dynamically based on items in an array. For context, I could have dozens of schedules with 20+ class types.
You can work with a Set, isSubset will return true if the schedules element contains all elements of the searchSet
let searchSet = Set(searchArray)
var filteredSchedules = schedules.filter { searchSet.isSubset(of: $0.classTypes) }
As suggested by #LeoDabus it might be worth changing the type of classTypes to Set instead of arrays (if order doesn't matter) since they seems to be unique and then the filtering can be done in the opposite way without the need to convert searchArray each time
var filteredSchedules = schedules.filter { $0.classTypes.isSuperset(of: searchArray) }
The problem with the ECMA standard for sort of Object.keys() is known:
Object.keys() handle all keys with integer (example: 168), including integer as strings (example: "168"), as a integer. The result is, both are the same (168 === "168"), and overwrite itself.
var object = {};
object["168"] = 'x';
object[168] = 'y';
Object.keys(object); // Array [ "168" ]
object[Object.keys(object)]; // "y"
Interestingly, all keys (including pure integer keys) are returned as a string.
The ecma262 wrote about this: All keys will be handle as a integer, expect the key is a String but is not an array index.
https://tc39.es/ecma262/#sec-ordinaryownpropertykeys
That should tell us: 168 === "168". A toString() do not solve the problem.
var object = {};
object[[3].toString()] = 'z';
object[[1].toString()] = 'x';
object[[2].toString()] = 'y';
Object.keys(object);
// Array(3) [ "1", "2", "3" ]
Paradoxically, in this case, only integer apply as "enumerable" (it's ignoring array.sort(), that sort also strings with letters.).
My question about this is simple: How can i prevent the sort function in Object.keys()? I have testet the Object.defineProperties(object, 1, {value: "a", enumerable: true/false}), but that mean not realy enumerable in the case of integer or string or integer-like string. It means only should it be counted with or not. It means "counted" like omit (if it false), not "enumerabled" like ascending or descending.
A answere like that is not a good answer: Please use only letters [a-zA-Z] or leastwise a letter at the first position of keyword.
What I want: That the keys are not sorted, but output in the order in which they were entered, whether integer, string or symbol.
Disclaimer: Please solutions only in JavaScript.
Javascript Objects are unordered by their nature. If you need an ordered object-like variable I would suggest using a map.
To achieve what you're looking for with a map instead of object you'd do something like the below:
var map1 = new Map();
map1.set("123", "c");
map1.set(123, "b");
var iterator1 = map1.keys();
var myarray = [];
for (var i = 0; i < map1.size; i++) {
myarray.push(iterator1.next().value);
}
console.log(myarray);
// Array ["123", 123]
Unfortunately it's not compatible with IE and I'm not sure how else you could achieve what you need without it. A quick Google did return something about jQuery maps, though.
If you don't want to use jQuery and still need to support IE some points are below:
Is there anything stopping you using an array rather than JS object to store the data you need? This will retain the order per your requirements unlike objects. You could have an object entry in each iteration which represents the key then use a traditional foreach to obtain them as an array. I.e.
The array:
var test_array = [
{key: 123, value: 'a value here'},
{key: "123", value: 'another value here'}
];
// console.log(test_array);
Getting the keys:
var test_array_keys = [];
test_array.forEach(function(obj) { test_array_keys.push(obj['key']); } );
// console.log(test_array_keys);
Then if you needed to check whether the key exists before adding a new entry (to prevent duplicates) you could do:
function key_exists(key, array)
{
return array.indexOf(key) !== -1;
}
if(key_exists('12345', test_array_keys))
{
// won't get here, this is just for example
console.log('Key 12345 exists in array');
}
else if(key_exists('123', test_array_keys))
{
console.log('Key 123 exists in array');
}
Would that work? If not then the only other suggestion would be keeping a separate array alongside the object which tracks the keys and is updated when an entry is added or removed to/from the object.
Object Keys sorted and store in array
First Creating student Object. then sort by key in object,last keys to store in array
const student={tamil:100, english:55, sci:85,soc:57}
const sortobj =Object.fromEntries(Object.entries(student).sort())
console.log(Object.keys(sortobj))
use map instead of an object.
let map = new Map()
map.set("a", 5)
map.set("d", 6)
map.set("b", 12)
to sort the keys (for example, to update a chart data)
let newMap = new Map([...map.entries()].sort())
let keys = Array.from(newMap.keys()) // ['a','b','d']
let values = Array.from(newMap.values()) // [5,12,6]
I need to check the existence of some elements in an array as such
I have an array as such
ar = ['one','two','three']
I want to know how I can individually check the elements in the regular expression code below instead of "/something/" that would map through my array and check if they exist in graphQL one by one.
similar : allCockpitHello (filter: {Association : {value : {regex: "\/something/" }}} limit:2){
nodes{
Name{
value
}
}
You need to have the regex string as an input parameter to be used by the resolver, GraphQL is not going to do the filter for you, you need to do/call that logic in the resolver based on your inputs.
Based on your example, you could have something like this on the schema and resolver:
type Node {
name: String!
}
type NodeQueries {
nodes (filterRegEx :String): [Node]!
}
Once you have the input string on the resolver, the implementation of the filter mechanism is up to you.
const resolvers = {
...
NodeQueries: {
nodes: (parent, params) => {
const {filterRegEx} = params; // regex input string
const ar = ['one','two','three'];
// Create a RegExp based on the input,
// Compare the with the elements in ar and store the result...
// You might end up with ... res = ['one', 'three'];
// Now map the result to match your schema:
return _.map(res, name => ({name}) ); // to end up with [{name: 'one'}, {name: 'three'}]
}
}
...
}
GraphQL is not a magic bullet - it's only a query language, it 'transports' your needs to the engine (local client, remote server ...) where all the necessary processing takes place.
In this case you probably need to pass your array and expression as variables to the server (resolver). If processing is expensive results (similar relation) should be already defined, cached, preprocessed, etc.
If dataset is small you can do this entirely client-side - iterate over an array (fetched using graphql).
I want to sort an Array of objects, by the properties it shares with another Array of objects
struct GeneralComposition : Decodable {
let id, formId, relationId, fixedContentTypeId, separatorId: Int
let orderBy: Int
}
struct FixedContentType: Decodable {
let name, htmlType: String
let isEditable: Int
let typeId : String
}
var fixedContentType = [FixedContentType]()
var generalComposition = [GeneralComposition]()
In GeneralComposition I get the order the items must have, with orderBy, and then take every item's fixedContentTypeID, compare with the typeId in FixedContentType to get the order in which this content must be showed in screen.
Any idea about how can it be done?
Thanks!
You can build a dictionary for the fixedContentTypeID’s of generalComposition:
let order = generalComposition.reduce(into: [Int: Int]()) { result, value in
result[value.fixedContentTypeId] = value.orderBy
}
You now have an efficient way to lookup the orderBy value for a given typeId within your array of FixedContentType objects. You can use that for sorting:
fixedContentType.sort {
(order[$0.typeId] ?? 0) < (order[$1.typeId] ?? 0)
}
By the way, your typeId is a String, and fixedContentTypeId is an Int. I’m assumed that was a typo introduced when preparing the question, and that they’re really both Int. If they’re really different types (which would be weird), the solution would be similar, though you’d have to do some conversions. But I didn’t want to go there unless you confirmed that this is really what you model was.
But, given that your typeId really is a String, you could make your dictionary a [String: Int]:
let order = generalComposition.reduce(into: [String: Int]()) { result, value in
result[String(value.fixedContentTypeId)] = value.orderBy
}