I want to iterate a map but its giving "unknown identifier referenced in the spl program" on line 2.
logic state: { mutable map<uint32,rstring> ageNameMap ={};
mutable MapIterator it;//2
}
Any idea how to fix this?
for (unit32 in ageNameMap){
...
}
This resolved my problem.
Related
I had working code to remove all map annotations with a button, but after my update to xcode 7 I am running into the error:
Type 'MKAnnotation' does not conform to protocol 'SequenceType'
if let annotations = (self.mapView.annotations as? MKAnnotation){
for _annotation in annotations {
if let annotation = _annotation as? MKAnnotation {
self.mapView.removeAnnotation(annotation)
}
}
}
In Swift 2 annotations is declared as non optional array [MKAnnotation] so you can easily write
let allAnnotations = self.mapView.annotations
self.mapView.removeAnnotations(allAnnotations)
without any type casting.
self.mapView.removeAnnotations(self.mapView.annotations)
If you don't want remove user location.
self.mapView.annotations.forEach {
if !($0 is MKUserLocation) {
self.mapView.removeAnnotation($0)
}
}
Note: Objective-C now have generics, it is no longer necessary cast the elements of 'annotations' array.
SWIFT 5
If you don't want to remove user location mark:
let annotations = mapView.annotations.filter({ !($0 is MKUserLocation) })
mapView.removeAnnotations(annotations)
The issue is that there are two methods. One is removeAnnotation which takes an MKAnnotation object, and the other is removeAnnotations which takes an array of MKAnnotations, note the "s" at the end of one and not the other. Attempting to cast from [MKAnnotation], an array to MKAnnotation a single object or visa versa will crash the program. The line of code self.mapView.annotations creates an array. Thus, if you are using the method removeAnnotation, you need to index the array for a single object within the array, as seen below:
let previousAnnotations = self.mapView.annotations
if !previousAnnotations.isEmpty{
self.mapView.removeAnnotation(previousAnnotations[0])
}
Thus, you can remove various annotations while keeping the users location. You should always test your array before attempting to remove objects from it, else there is the possibly getting an out of bounds or nil error.
Note: using the method removeAnnotations (with an s)removes all annotations.
If you are getting a nil, that implies that you have an empty array. You can verify that by adding an else statement after the if, like so;
else{print("empty array")}
Reading Apple's Swift guide, more specifically the Closures chapter I've stumbled upon a problem. A String array is declared
var names = ["Cris", "Alex", "Ewa", "Barry", "Daniella"]
The purpose of this section is to pass an array of Strings (the one above) and with the function sort(_:) have the same array back but sorted using an auxiliary method by providing a closure. The closure is the method backwards
func backwards(s1: String, s2: String) -> Bool {
return s1 > s2
}
Then an array, reversed, is declared and applied the method sort to the original array, names:
var reversed = names.sort(backwards)
AFAIK reversed should be inferred as an array of Strings but when I check it is inferred as var reversed: <>. Now, reversed doesn't store anything and an error pops up:
Immutable value of type '[String]' only has mutating members named 'sort'
Later on in the chapter the closure is simplified a lot but I get the same error as now so I tried to fix it when the expression is simple enough but I have no clue on what to do.
I don't know if the book forgot something or is my mistake, help will be appreciated. Thank you in advance!
I have the following problem. I use this code below and I get the issue
"Variable 'characteristic' was never mutated; consider changing to
'let' constant"
for var characteristic:CBCharacteristic in service.characteristics ?? [] {
print(str)
_selectedPeripheral!.writeValue(str.dataUsingEncoding(NSUTF8StringEncoding)!, forCharacteristic: characteristic, type: CBCharacteristicWriteType.WithoutResponse)
}
When I change to "let", there's an Error:
'let' pattern cannot appear nested in an already immutable context
Why does it recommend me the change and afterwards mark it as an error?
You just need to remove var, making your code:
for characteristic in service.characteristics ?? [] {
print(str)
_selectedPeripheral!.writeValue(str.dataUsingEncoding(NSUTF8StringEncoding)!, forCharacteristic: characteristic, type: CBCharacteristicWriteType.WithoutResponse)
}
because characteristic is immutable by default.
I'd like to test the value of an enumeration attribute of a DOORs object. How can this be done? And where can I find a DXL documentation describing basic features like this?
if (o."Progress" == 0) // This does NOT work
{
// do something
}
So after two weeks and an expired bounty I finally made it.
Enum-Attributes can be assigned to int or string variables as desired. But you have to assign to a variable to perform such a conversion. It is not casted when a mere comparison is done like in my example. So here comes the solution:
int tmp = o."Progress"
if (tmp == 0)
{
// do something
}
When tmp is a string, a comparison to the enum literals is possible.
That was easy. Wasn't it? And here I finally found the everything-you-need-to-know-about-DXL manual.
For multi-valued enumerations, the best way is if (isMember(o."Progress", "0")) {. The possible enumerations for single and multi-enumeration variables are considered strings, so Steve's solution is the best dxl way for the single enumeration.
You can also do
if(o."Progress" "" == "0")
{
//do something
}
This will cast the attribute value to a string and compare it to the string "0"
If you're talking about the "related number" that is assignable from the Edit Types box, then you'll need to start by getting the position of the enumeration string within the enum and then retrieve EnumName[k].value .
I'm no expert at DXL, so the only way to find the index that I know of off the top of my head is to loop over 1 : EnumName.size and when you get a match to the enumeration string, use that loop index value to retrieve the enumeration "related number."
I have a ptr_vector list of my own objects. Something like this:
boost::ptr_vector<SomeClass> *list;
list->push_back(new SomeClass()>;
...
BOOST_FOREACH(SomeClass *tempObj, list) // [x]
{
tempObj->...
}
>‘boost::ptr_vector<SomeClass>*’ is not a class, struct, or union type
I think your problem is that you declared 'list' as a pointer to a boost::ptr_vector and are trying to use it as an automatic object.
IMHO the first line of your code snippet should read:
boost::ptr_vector<SomeClass> list;