I'm trying to add value into [[String: String]]() as follow:
let realm = try! Realm()
let nrcObj = realm.objects(ObjectNRC.self)
for nrc in nrcObj {
nrcTownshipCode["value"] = nrc.regionCode
nrcTownshipCode["display"] = nrc.regionCode
}
But when I did like that, I've encountered following error message.
Cannot subscript a value of type '[[String : String]]' with an index
of type 'String'
Please suggest me how to do it. Thanks.
What are you trying to do is to treat [[String: String]] as dictionary which is not! Actually, [[String: String]] is an array of dictionaries ([String: String]). So what would you need to do instead -for instance-:
for nrc in nrcObj {
nrcTownshipCode[0]["value"] = nrc.regionCode
nrcTownshipCode[0]["display"] = nrc.regionCode
}
means that you would iterate through nrcObj and append values for the first dictionary in your array. Note that it might not be your desired result, but it describes your issue and how you could fix it. For instance, you might want to add an additional variable to hold the iteration count and use it as an index for your array:
var i = 0
for nrc in nrcObj {
nrcTownshipCode[i]["value"] = nrc.regionCode
nrcTownshipCode[i]["display"] = nrc.regionCode
i += 1
}
Related
I have an array of custom objects but when I add items to array it creates duplicate of last item add in array.
Below is my code, please suggest where is the mistake, this small thing not able to get it.
var tempArr:[AnimalViewModel] = [AnimalViewModel]()
do {
var objAnimal = Animal()
var result = try managedContext.fetch(fetchRequest)
for ds in result as! [NSManagedObject] {
objAnimal.name = (ds.value(forKey: "name")) as! String
objAnimal.type = (ds.value(forKey: “type”)) as! String
Var objAVM = AnimalViewModel(aniModel: objAnimal)
tempArr.append(objAVM)
}
} catch {
print(" Error ")
}
The array tempArr contains all duplicate element as last inserted element even objAnimal contains different values.
Thanks,
First of all never print a meaningless literal string like "Error" in a catch block. Print always the error instance.
Animal is obviously a class (reference type). You are creating one instance and the properties are updated in the loop. As always the same instance is used the values are overwritten and you get result.count items with the same contents.
Create new instances inside the loop and replace Entity with the real entity name
var tempArr = [AnimalViewModel]()
do {
let result = try managedContext.fetch(fetchRequest) as! [Entity] // let !
for ds in result {
let objAnimal = Animal() // let !
objAnimal.name = ds.name
objAnimal.type = ds.type
let objAVM = AnimalViewModel(aniModel: objAnimal) // let !
tempArr.append(objAVM)
}
} catch {
print(error)
}
And please notice and fix the warnings about never mutated variables
I just want to create a dictionary with the help of for loop
sample code :
var counter: Int = 1;
var pageCountDict = [String:Any]();
for filterCount in counter..<6
{
if let count = "page_\(filterCount)_vtime" as? String
{
pageCountDict = [count: timeInterval_Int];
}
}
print(pageCountDict);
This print command give me only last value of forloop
I just want all the value of this variable pageCountDict in a dictonary
The way to assign to a dictionary is first use the subscript and assign the value to it:
pageCountDict[YourKey] = YourValue
Also, you can see many examples and explanations in Apple documentation regarding dictionaries.
With each loop, you are replacing the dictionary with one that contains only one element. What you want to do is this :
pageCountDict[count] = timeInterval_Int
Also, you shouldn't need the as? String part. This should be sufficient :
for filterCount in counter..<6
{
pageCountDict[count] = "page_\(filterCount)_vtime"
}
var pageCountDict = [String:Any]()
You can add values to this dictionary by merging previous contents and new data as follows...
let counter: Int = 1
var pageCountDict = [String:Any]()
for filterCount in counter..<6
{
let value = 9
let count = "page_\(filterCount)_vtime" //'if' is not needed as it is always true
pageCountDict.merge([count: timeInterval_Int], uniquingKeysWith:{ (key, value) -> Any in
//assign value for similar key
timeInterval_Int
})
}
print(pageCountDict)`
How do I create and append to an associative array in Swift? I would think it should be something like the following (note that some values are strings and others are numbers):
var myArray = []
var make = "chevy"
var year = 2008
var color = "red"
myArray.append("trackMake":make,"trackYear":year,"trackColor":color)
The goal is to be able to have an array full of results where I can make a call such as:
println(myArray[0]["trackMake"]) //and get chevy
println(myArray[0]["trackColor"]) //and get red
Simply like this:
myArray.append(["trackMake":make,"trackYear":year,"trackColor":color])
Add the brackets. This will make it a hash and append that to the array.
In such cases make (extensive) use of let:
let dict = ["trackMake":make,"trackYear":year,"trackColor":color]
myArray.append(dict)
The above assumes that your myArray has been declared as
var myArray = [[String:AnyObject]]()
so the compiler knows that it will take dictionary elements.
I accept above answer.It is good.Even you have given correct answer,I like to give simplest way.The following steps are useful,if you guys follow that.Also if someone new in swift and if they go through this,they can easily understand the steps.
STEP 1 : Declare and initialize the variables
var array = Array<AnyObject>()
var dict = Dictionary<String, AnyObject>()
var make = "chevy"
var year = 2008
var color = "red"
STEP 2 : Set the Dictionary(adding keys and Values)
dict["trackMake"] = make
dict["trackYear"] = year
dict["trackColor"] = color
println("the dict is-\(dict)")
STEP 3 : Append the Dictionary to Array
array.append(dict)
println("the array is-\(array)")
STEP 4 : Get Array values to variable(create the variable for getting value)
let getMakeValue = array[0]["trackMake"]
let getYearValue = array[0]["trackYear"]
let getColorValue = array[0]["trackColor"]
println("the getMakeValue is - \(getMakeValue)")
println("the getYearValue is - \(getYearValue)")
println("the getColorVlaue is - \(getColorValue)")
STEP 5: If you want to get values to string, do the following steps
var stringMakeValue:String = getMakeValue as String
var stringYearValue:String = ("\(getYearValue as Int)")
var stringColorValue:String = getColorValue as String
println("the stringMakeValue is - \(stringMakeValue)")
println("the stringYearValue is - \(stringYearValue)")
println("the stringColorValue is - \(stringColorValue)")
STEP 6 : Finally the total output values are
the dict is-[trackMake: chevy, trackColor: red, trackYear: 2008]
the array is-[{
trackColor = red;
trackMake = chevy;
trackYear = 2008;
}]
the getMakeValue is - Optional(chevy)
the getYearValue is - Optional(2008)
the getColorVlaue is - Optional(red)
the stringMakeValue is - chevy
the stringYearValue is - 2008
the stringColorValue is - red
Thank You
This sounds like you are wanting an array of objects that represent vehicles. You can either have an array of dictionaries or an array of vehicle objects.
Likely you will want to go with an object as Swift arrays and dictionaries must be typed. So your dictionary with string keys to values of differing types would end up having the type [String : Any] and you would be stuck casting back and forth. This would make your array of type [[String : Any ]].
Using an object you would just have an array of that type. Say your vehicle object's type is named Vehicle, that would make your array of type [Vehicle] and each array access would return an instance of that type.
If I want to try it with my own statement. Which also I want to extend my array with the data in my dictionary and print just the key from dictionary:
var myArray = ["Abdurrahman","Yomna"]
var myDic: [String: Any] = [
"ahmed": 23,
"amal": 33,
"fahdad": 88]
for index in 1...3 {
let dict: [String: Any] = [
"key": "new value"
]
// get existing items, or create new array if doesn't exist
var existingItems = myDic[myArray] as? [[String: Any]] ?? [[String: Any]]()
// append the item
existingItems.append(myArray)
// replace back into `data`
myDic[myArray] = existingItems
}
I've had troubles filtering array of keywords (strings) in swift ,My code:
self.filteredKeywords=filter(keywords.allValues, {(keyword:NSString) ->
Bool in
let words=keyword as? NSString
return words?.containsString(searchText)
})
As AnyObject can't be subtype of NSString, I'm stuck with this!
[Updated for Swift 2.0]
As NSString is toll-free bridged to Swift String, just avoid the coercions with:
3> ["abc", "bcd", "xyz"].filter() { nil != $0.rangeOfString("bc") }
$R1: [String] = 2 values {
[0] = "abc"
[1] = "bcd"
}
But, if you think allValues aren't strings:
(keywords.allValues as? [String]).filter() { nil != $0.rangeOfString("bc") }
which returns an optional array.
Your filter is over [AnyObject], but your closure takes NSString. These need to match. Also, your result needs to be a Bool, not a Bool?. You can address these simply like this:
self.filteredKeywords = filter(keywords.allValues, {
let keyword = $0 as? NSString
return keyword?.containsString(searchText) ?? false
})
This accepts AnyObject and then tries to coerce it down to NSString. It then nil-coalleces (??) the result to make sure it always is a Bool.
I'd recommend, though, treating keywords as a [String:String] rather than an NSDictionary. That would get rid of all the complications of AnyObject. Then you can just do this:
self.filteredKeywords = keywords.values.filter { $0.rangeOfString(searchText) != nil }
Whenever possible, convert Foundation collections into Swift collections as soon as you can and store those. If you have incoming Foundation objects, you can generally convert them easily with techniques like:
let dict = nsdict as? [String:String] ?? [:]
Or you can do the following to convert them such that they'll crash in debug (but silently "work" in release):
func failWith<T>(msg: String, value: T) -> T {
assertionFailure(msg)
return value
}
let dict = nsdict as? [String:String] ?? failWith("Couldn't convert \(d)", [:])
Swift 4.2 provides a new way to do this:
var theBigLebowski = ["The Dude", "Angry Walter", "Maude Lebowski", "Donny Kerabatsos", "The Big Lebowski", "Little Larry Sellers"]
// after removeAll -> ["The Dude", "Angry Walter", "Donny Kerabatsos", "Little Larry Sellers"]
theBigLebowski.removeAll{ $0.contains("Lebowski")}
print(theBigLebowski)
There is both a problem with GoZoner's answer for certain data types and also a slightly better way to do this. The following examples can show this:
let animalArray: NSMutableArray = ["Dog","Cat","Otter","Deer","Rabbit"]
let filteredAnimals = animalArray.filter { $0.rangeOfString("er") != nil }
print("filteredAnimals:", filteredAnimals)
filteredAnimals: [Dog, Cat, Otter, Deer, Rabbit]
Likely not the set you expected!
However this works fine this way if we don't type animalArray as an NSMutableArray:
let animalArray = ["Dog","Cat","Otter","Deer","Rabbit"]
let filteredAnimals = animalArray.filter { $0.rangeOfString("er") != nil }
print("filteredAnimals:", filteredAnimals)
filteredAnimals: [Otter, Deer]
However I'd recommend using $0.contains() instead of $0.rangeOfString() != nil because it functions in both circumstances and slightly enhances the readability of the code:
let animalArray: NSMutableArray = ["Dog","Cat","Otter","Deer","Rabbit"]
let filteredAnimals = animalArray.filter { $0.contains("er") }
print("filteredAnimals:", filteredAnimals)
filteredAnimals: [Otter, Deer]
I am trying to get all the key values of NSMutableDictionary as String Array. I am using this myNSMutableDictionary.allkeys to get the values as an Array but I cannot find a way to unwrap the key values.
This is what I have tried so far:
for (key, _) in NSMutableDictionary {
println("THIS IS MY NEW KEY\(key)")
}
And I tried this
var myArray:NSArray = myNSMutableDictionary.allKeys
var string:NSString? = uniqueIDArray[0] as? NSString
println("This is unwraped value\(string!)")
And this
var myArray:Array = myNSMutableDictionary.allKeys
println("This is unwraped value\(myArray[0])")
I keep getting the value as Optional("kMSZgoTmiX") instead of kMSZgoTmiX which is the key value I need
Thank you for all your help!
So you've got a dictionary with values that are strings (and keys that are something, assume String):
var dictionaryOfStringValues : [String:String] = /* your dictionary */
And you want to iterate over the contents:
for (key, val) in dictionaryOfStringValues {
// use key and val
}
If you just want the values in a way you can easily iterate over:
var theValues = dictionaryOfStringValues.values
If you insist that theValues be an Array:
var theValuesAsAnArray = Array(dictionaryOfStringValues.values)
If you are starting with an NSMutableDictionary, then convert it at the point where it FIRST ENTERS your Swift code into a Swift Dictionary. Use an as variant to do that. After that, pure Swift.
Like this:
7> for (key, value) in ["a":1, "b":2] {
8. println (key)
9. println (value)
10. }
b
2
a
1
let myNSMutableDictionary = NSMutableDictionary()
myNSMutableDictionary["myKey1"] = 5
myNSMutableDictionary["myKey2"] = 10
myNSMutableDictionary["myKey3"] = 15
let myKeysArrayUnsorted = myNSMutableDictionary.allKeys as [String]
let myValuesArrayUnsorted = myNSMutableDictionary.allValues as [Int]
let keyString = myKeysArrayUnsorted[0] // "myKey2"
let keyValue = myNSMutableDictionary[keyString] as Int // 10
println("This is my first unsorted key \(keyString) = \(keyValue)")
let myKeysArraySorted = (myNSMutableDictionary.allKeys as [String]).sorted(<)
for key in myKeysArraySorted {
println(myNSMutableDictionary[key]!) // 5 10 15
}