I am stuck on this code! I want to convert an AnyObject to String what is the best way to do that?
In this little Code-snippet below I try to convert the Result of an Realm query to String. But at the end I can't remove the Optional. Have a look:
print(Object)
// Print:
//Results<Subject> (
// [0] Subject {
// id = 10;
// name = Englisch;
// short = Eng;
// mainSubject = 1;
//}
let name = Object.valueForKey("name")
print(name)
// Print:
//Optional((
// Englisch
//))
let newname = name as! String
// Here I try to convert the AnyObject from above to a Swift-String but this don't work!
// Error: Could not cast value of type '__NSArrayM' (0x7fff7db48c18) to 'NSString' (0x7fff7e4ed268).
print(newname)
// Will never be executed
Can someone help me please?
Thanks
Michael
Here's the answer:
let name = Object.valueForKey("name") as! [String]
let newName = name.first!
print(newName)
This is not elegant but it works ;-)
and sorry that I can't vote yet. But when I've earned 15 reputation, my votes will become public
You can try
let name = Object.valueForKey("name").stringValue!
print(name) //Should print: Englisch
Don't know whether this will work for you or not. But it should, I guess.
Your problem is that the name property is of type NSMutableArray (__NSArrayM in the error message) so you should cast it to [String].
Related
I am having difficulty in converting an Int32 to String. I tried to following:
String(cartItem?.quantity)
"\(cartItem?.quantity)"
but no luck.
cart.quantity is of type Int32.
quantity is an attribute of cart in the CoreData model.
The question isn't clear but what I think this issue boils down to is that you can't init a string with an optional value.
So either do as #matt suggested and force unwrap the cartItem
String(cartItem!.quantity)
or supply a default value
String(cartItem?.quantity ?? 0)
Of course if you need to handle the fact that you might not have a cart then it is better to do it like
if let cart = cartItem {
let str = "\(cart.quantity)" //or String(cart.quantity)
//do stuff with str
} else {
//handle no cart state
}
you can by declare string and data
var arrayOf32Int: [UInt32] = [1,32,100,984,13,542]
let data = Data(bytes: arrayOf32Int, count: arrayOf32Int.count * MemoryLayout<UInt32>.stride)
let string = String(data: data, encoding: .utf32LittleEndian)!
print(string)
I am using firebase to retrieve a list of data then convert it to an NSDictonary array. I want to parse the data by a property e.g name
func getAllMyModels() {
if let e = email {
_ = ref.child("childName").queryOrdered(byChild: "email").queryEqual(toValue: e).observe(.value) { snapshot in
var dictionary = [NSDictionary]()
let children = snapshot.children
while let rest = children.nextObject() as? DataSnapshot, let value = rest.value {
dictionary.append(NSDictionary(dictionary: value as! [String: Any]))
}
let names = dictionary.flatMap {$0["name"]} // names print correct values
let set = Set(names)
print(set)
}
}
}
This code can't be complied the error is:
Showing Recent Messages
Command failed due to signal: Segmentation fault: 11
If i removed this line:
let set = Set(Array(names))
all works fine.
I also tested by replace it by this block
let ar = ["name1","name2"].flatMap { return $0 }
Set(ar)
No errors.
Not sure why? Who can tell, thanks!
EDIT: Even though the element in the array is String type but the names array is [Any], so the solution is
let names = dictionary.flatMap {$0["name"]} as! [String]
I think this errors occurs because the Array you generate from the dictionary with flatMap is an Array of Any and not a String Array, try to cast to a String like this:
...
let names = dictionary.flatMap {$0["name"] as? String}
let set = Set(Array(names))
...
Hope this help you
Cast names to [String]:
let names = dictionary.flatMap {$0["name"]} as! [String]
Trying to get substring of String and append it to array of Strings:
var stringToSplit = "TEST TEXT"
var s = [String]()
let subStr = anotherString[0 ..< 6]
s.append(subStr) // <---- HERE I GET THE ERROR
As #Leo Dabus mentioned, you need to initialize a new String with your substring:
Change:
s.append(subStr)
To:
s.append(String(subStr))
my two cents for serro in different context.
I was trying to get an array of "String" splitting a string.
"split" gives back "Substring", for efficiency reason (as per Swift.org litre).
So I ended up doing:
let buffer = "one,two,three"
let rows = buffer.split(separator:",")
let realStrings = rows.map { subString -> String in
return String(subString)
}
print(realStrings)
Ape can help someone else.
there. I am a beginner in Swift and am trying to convert an older program to Swift3. I´ve managed to fix a bunch of errors, but I cannot get this function to work.
fileprivate func extractEntitlements(_ entitlementData: Data) -> NSDictionary? {
var originalEntitlementsData = entitlementData
let xmlStart = "<?xml".data(using: String.Encoding.ascii, allowLossyConversion: true)
let bytes = (originalEntitlementsData as NSData).bytes
for i in 0...(originalEntitlementsData.count - xmlStart!.count) {
if memcmp((xmlStart! as NSData).bytes, bytes + i, Int(xmlStart!.count)) == 0 {
let end = originalEntitlementsData.count - i
**originalEntitlementsData = originalEntitlementsData.subdata(in: NSMakeRange(i, end))**
break;
}
}
return NSString(data: originalEntitlementsData, encoding: String.Encoding.ascii.rawValue)?.propertyList() as? NSDictionary
}
Here is the error I get:
There are a bunch of questions regarding this error, but I am not being successful implementing a solution. Any tips on how I should proceed?
Thanks guys!
Ranges are more complicated and simpler at the same time in swift.
You want subdata(in: start..<end), which makes a Range<Int>, which is the type you need. However, in this case start and end refer to the beginning and end indexes of the range, not the location and length as you pass to NSMakeRange().
As #jrturton already said, subdata(in:) takes a Range<Int> argument,
so it should be
originalEntitlementsData = originalEntitlementsData.subdata(in: i..<i+end)
in your case. But note that all the conversions to NSData, taking
the .bytes, explicit loop and memcmp are not needed if you
take advantage of the existing range(of:) method of Data:
var originalEntitlementsData = entitlementData
let xmlStart = "<?xml".data(using: .utf8)!
if let range = originalEntitlementsData.range(of: xmlStart) {
originalEntitlementsData = originalEntitlementsData.subdata(in: range.lowerBound..<originalEntitlementsData.endIndex)
// Alternatively:
// originalEntitlementsData.removeSubrange(0..<range.lowerBound)
}
I get an error when declaring i
var users = Array<Dictionary<String,Any>>()
users.append(["Name":"user1","Age":20])
var i:Int = Int(users[0]["Age"])
How to get the int value?
var i = users[0]["Age"] as Int
As GoZoner points out, if you don't know that the downcast will succeed, use:
var i = users[0]["Age"] as? Int
The result will be nil if it fails
Swift 4 answer :
if let str = users[0]["Age"] as? String, let i = Int(str) {
// do what you want with i
}
If you are sure the result is an Int then use:
var i = users[0]["Age"] as! Int
but if you are unsure and want a nil value if it is not an Int then use:
var i = users[0]["Age"] as? Int
“Use the optional form of the type cast operator (as?) when you are
not sure if the downcast will succeed. This form of the operator will
always return an optional value, and the value will be nil if the
downcast was not possible. This enables you to check for a successful
downcast.”
Excerpt From: Apple Inc. “The Swift Programming Language.” iBooks.
https://itun.es/us/jEUH0.l
This may have worked previously, but it's not the answer for Swift 3. Just to clarify, I don't have the answer for Swift 3, below is my testing using the above answer, and clearly it doesn't work.
My data comes from an NSDictionary
print("subvalue[multi] = \(subvalue["multi"]!)")
print("as Int = \(subvalue["multi"]! as? Int)")
if let multiString = subvalue["multi"] as? String {
print("as String = \(multiString)")
print("as Int = \(Int(multiString)!)")
}
The output generated is:
subvalue[multi] = 1
as Int = nil
Just to spell it out:
a) The original value is of type Any? and the value is: 1
b) Casting to Int results in nil
c) Casting to String results in nil (the print lines never execute)
EDIT
The answer is to use NSNumber
let num = subvalue["multi"] as? NSNumber
Then we can convert the number to an integer
let myint = num.intValue
if let id = json["productID"] as? String {
self.productID = Int32(id, radix: 10)!
}
This worked for me. json["productID"] is of type Any.
If it can be cast to a string, then convert it to an Integer.