I am really new to swift and trying to understand ios programming. Basically I have a table where "id" and "fact" columns. id is primary key'd and here is the swift fuction I am trying to query the values
func getItemsFromRow(fact_cid: String) ->[FactsData]{
var rowData: [FactsData]!
let rawQ = "select * from facts where \(facts_id)=?"
if (openDatabase()){
do{
let results = try database.executeQuery(rawQ, value(forKey: fact_cid))
while results.next(){
let currentFact = FactsData(factid: results.string(forColumn: facts_id), factsdata: results.string(forColumn: facts_fld))
if rowData == nil {
rowData = [FactsData]()
}
rowData.append(currentFact)
}
}
}
return rowData
}
But this line gives me error
let results = try database.executeQuery(rawQ, value(forKey: fact_cid))
Error is
Cannot invoke 'executeQuery' with an argument list of type '(String, Any?)'
I am trying to pass the id as string. Not sure what I am doing wrong here.
Any help is much appreciated.
Change it to
let results = try database.executeQuery(rawQ, values: [fact_cid])
since the second parameter should be an array
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)`
might sound like a basic question--but I'm not seeing where I am going wrong..
I end up with either of these two scenarios:
I keep getting the error "Could not cast value of type __NSCFNumber to NSSTring". if I use extractedSku = skuList[i]!.value["sku"] as! String
If I remove as! String it saves it, but it isn't saved as a string. How do I get this to be saved as a string?
I have appended data from firebase into an array
skuArray = [AnyObject?]()
in viewDidLoad, I am iterating skuArray to extract the 'sku' and store into a variable.
var skuArray = [AnyObject?]()
var productDetailArray = [AnyObject?]()
data stored in Sku Array is:
[Optional(Snap (aRandomKey) {
active = 1;
sku = 888888;
})]
viewDidLoad:
let skuList = self.skuArray
for var i = 0; i < skuList.count ; ++i{
let extractedSku = skuList[i]!.value["sku"] as! String
// go into database and extract "products" details by sku
self.databaseRef.child("products/\(extractedSku)").observeEventType(.ChildAdded, withBlock: { (snapshot:FIRDataSnapshot) in
self.productDetailArray.append(snapshot)
})
Since the underlying type is NSNumber, use the stringValue property to get a String:
if let extractedSku = (skuList[i]?.value["sku"] as? NSNumber)?.stringValue {
// use extractedSku which is of type String
}
I have parser in Objc, parser returns NSDictionary. I am using this parser in swift class. But when some value is missing on that dictionary, it shows nil value. e.g. ->
wirlessData = {
"anon" = {
};
"channel" = {
"text" = 1;
};
}
I am checking through
if let wepauthValue = wirlessData["wepauth"] {
if let value = wepauthValue["text"] {
print("\(value)") // nil
}
}
I don't how it satisfy the if let condition. Any one faced this types of problem can help me out.
Thanks,
vikash
You don't need any special code to do this, because it is what a dictionary already does. When you fetch dict[key] you know whether the dictionary contains the key, because the Optional that you get back is not nil (and it contains the value).
So, if you just want to answer the question whether the dictionary contains the key, ask:
let keyExists = dict[key] != nil
If you want the value and you know the dictionary contains the key, say:
let val = dict[key]!
But if, as usually happens, you don't know it contains the key - you want to fetch it and use it, but only if it exists - then use something like if let:
if let val = dict[key] {
// now val is not nil and the Optional has been unwrapped, so use it
}
I have tested it and found that value is still optional.Take a look at screenshot below to understand it better.
"anon" would be an empty dictionary. An empty dictionary is not nil, it is a dictionary. Just an empty one. A JSON parser will never, ever give nil values unless you ask for a key that is not in a dictionary. For example wirlessData ["nonexistingkey"] would give you nil.
If you be more type-strong about it with the if..let's then:
if let anonValue = wirlessData["anon"] {
if let value = anonValue["text"] as? String {
// This won't execute if value isn't converted from `anonvalue["text"]` to String specifically. This includes null been a false match too
print("\(value)") // nil
}else{
print("Value did't match string at all")
}
}
or even more specifically in your case:
if let anonValue = wirlessData["anon"] {
if let value = anonValue["text"] as? Int {
// This won't execute if value isn't converted from `anonvalue["text"]` to String specifically. This includes null been a false match too
print("\(value)") // nil
}else{
print("Value did't match int at all")
}
}
The value your parser is returning not nil, its empty so you need to check on count if inner data type is dictionary or array, I have past 1 sample here
Please use below code and correct your logic accordingly to get it work properly
let wirlessData:[String:AnyObject] = [
"anon" : [],
"channel" : [
"text" : 1
]
]
if wirlessData["anon"]?.count > 0 {
if let value = wirlessData["anon"]!["text"] {
print("\(value)") // nil
}
}
Try this below code using type check operator (is) -
if wirlessData["anon"] is [String:AnyObject]
{
let anon = wirlessData["anon"]!
print(anon)
if anon["random"] is String {
let stringValue = anon["random"]!
print("\(stringValue)")
}
else if anon["random"] is Int
{
let intValue = anon["random"]!
print("\(intValue)") // nil
}
else
{
print(" may be value did't match string & Int or nil ")
}
}
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]