I have a following snippet of code, that i am using for collection view category.
func indexPathForCategory(category: Category) -> NSIndexPath
{
let section = sections.index(of: category.section)
var item = 0
for (index, currentCategory) in categoriesForSection(index: section!).enumerated() {
if currentCategory === category {
item = index
break
}
}
return NSIndexPath(forItem: item, inSection: section!)
}
On the return statement, i get the error as Argument labels (forItem:,inSection:) do not match any available overloads.
Use NSIndexPath(item:section:) instead.
Related
I am doing a project for nand2tetris. We write a program in Jack and test it on VMEmulator. The class looks like this:
class List {
field int data;
field List next;
/* Creates a new List object. */
constructor List new(int car, List cdr) {
let data = car;
let next = cdr;
return this;
}
/* Disposes this List by recursively disposing its tail. */
method void dispose() {
if (~(next = null)) {
do next.dispose();
}
// Use an OS routine to recycle the memory held by this object.
do Memory.deAlloc(this);
return;
}
/* Prints the list*/
method void print() {
do Output.printString(" -> ");
do Output.printInt(data);
if (~(next = null)) {
do next.print();
}
return;
}
/* Inserts the argument in the right position of the list (ascending order)*/
method void insertInOrder(int ins){
var List prev, curr, insert;
let prev = this;
let curr = prev.getnext();
while (ins > prev.getdata()){
if (ins < curr.getdata()){
let insert = List.new(ins, curr);
do prev.setnext(insert);
}
else{
let prev = prev.getnext();
let curr = prev.getnext();
}
}
return;
}
/* Searches the argument in the list, if found, it returns the corresponding List object*/
method List find(int toFind){
var List temp;
var List equal;
var boolean found;
let temp = this;
let found = false;
while (~(next = null)){
if(toFind = temp.getdata()){
let equal = temp;
let found = true;
}
let temp = temp.getnext();
}
if (found){
return equal;
}
else{
return null;
}
}
method List getnext(){
return next;
}
method void setnext(List object){
let next = object;
return;
}
method int getdata(){
return data;
}
}
It has one private variable data and a pointer next. So I wrote getter and setter method to return those values. Other methods are fine only the getdata()method is incorrect. When it runs through the VMEmulator, it shows the error Out of segment space in List.getdata.3. This shows in the VMEmulator.
0function List.getdata0
1push argument0
2pop pointer0
3push this 0
4return
the error is at the 4th line return. When I change the Jack code, the same error is still at the 4th line.
What exactly is the problem in my getter method?
When you run a VM program on the VMEmulator you must first manually set the pointers to the various segments, otherwise you may get an "Out of segment space" error.
To understand the necessary settings, look at what the corresponding .tst file does. An alternative method is to insert the proposed code inside a function, since the function call automatically makes this type of setting.
You can get this error when you try to access member data of an object which is not constructed. Could it be that the List cdr in the constructor was not properly constructed?
I have a list of items and I want to edit its values before using it. I am using the map function to update each item in it. But the catch here is, I want to only update the items when the list size is 1. I want to return the list as it is if the size is larger than 1. How can I achieve this?
myList.map {
if(resources.getBoolean(R.bool.is_tablet) && it.itemList.size<6 && it.layerType == DOUBLE_LIST) {
it.layerType = SINGLE_LIST_AUTO
it.itemList.forEach {sectionItem->
sectionItem.layerType = SINGLE_LIST_AUTO
}
it
}else{
it
}
}
You can try using filter before map:
.filter { it.itemList.size == 1 }
I am assuming you want to modify the items in your list only if some conditions are met else return the same list unmodified.
You can consider using takeIf { } for this scenario if you desire to add some syntactic sugar
fun updateItemsInMyList(myList:List<SomeClass>): List<SomeClass> {
return myList
.takeIf {
// condition to modify items in your list
it.size > 1 && otherConditions
}
?.apply {
//update your items inside the list
}
?: myList // return the unmodified list if conditions are not met
}
If I understand your question correctly, you want to check if myList contains only one value else, you want update the values and return it. You could do something along the following lines,
myList.singleOrNull ?: myList.map {
if(resources.getBoolean(R.bool.is_tablet) && it.itemList.size<6 && it.layerType == DOUBLE_LIST) {
it.layerType = SINGLE_LIST_AUTO
it.itemList.forEach {sectionItem->
sectionItem.layerType = SINGLE_LIST_AUTO
}
it
}else{
it
}
}
return myList
Basically, check if there's only a single value in the list, if so, then return the value. In the case that there isn't (you get null), then you can map the value.
How can I use the Objective-C code below in Swift, I tried but something is wrong.
Objective-C:
NSUInteger index = [theArray indexOfObjectPassingTest:
^BOOL(NSDictionary *dict, NSUInteger idx, BOOL *stop)
{
return [[dict objectForKey:#"name"] isEqual:theValue];
}
];
Swift (Doesn't work):
let index = theArray.indexOfObjectPassingTest { (var dict: NSDictionary, var ind: Int, var bool: Bool) -> Bool in
return dict.objectForKey("name")?.isEqual("theValue")
}
I played with it and got this to work:
let theArray: NSArray = [["name": "theName"], ["name": "theStreet"], ["name": "theValue"]]
let index = theArray.indexOfObjectPassingTest { (dict, ind, bool) in return dict["name"] as? String == "theValue" }
if index == NSNotFound {
print("not found")
} else {
print(index) // prints "2"
}
This can be further reduced. As #newacct mentioned in the comment, the return can be dropped since the closure is only a single line. Also, _ can be used in place of the parameters that aren't being used:
let index = theArray.indexOfObjectPassingTest { (dict, _, _) in dict["name"] as? String == "theValue" }
You can get rid of the parameter list in the closure entirely and use the default $0 value. Note in that case, the three parameters are combined as a tuple, so the first value of the tuple dict is referenced as $0.0:
let index = theArray.indexOfObjectPassingTest { $0.0["name"] as? String == "theValue" }
Swift 3:
Consider this method:
public func index(where predicate: (Element) throws -> Bool) rethrows -> Int?
The following gives you an example how to use it:
let dict1 = ["name": "Foo"]
let dict2 = ["name": "Doh"]
let array = [dict1, dict2]
let index = array.index { (dictionary) -> Bool in
return dictionary["name"] == "Doh"
}
This returns the value 1.
Hope that helps
Guess you need this:
var index: UInt = theArray.indexOfObjectPassingTest({(dict: [NSObject: AnyObject], idx: UInt, stop: Bool) -> BOOL in return dict.objectForKey("name").isEqual(theValue)
})
I ended up using this for a Swift5 project:
let index = self.info.indexOfObject(passingTest: { (obj:Any, ind:Int, stop:UnsafeMutablePointer<ObjCBool>) -> Bool in
if let details = obj as? NSDictionary, let id = details["id"] as? Int
{
if (orderId == id)
{
stop.pointee = true
return true
}
}
return false;
})
Where orderId is id value of the object I wanted to find.
I have an array of PFObjects. I'd like to search if the "Type" contains "Sushi". The filter alters the array. How can I preform this search without altering the array?
func startCheckOptions(objects: [AnyObject]) {
let filteredArray = objects.filter() {
if let type = ($0 as PFObject)["Type"] as String {
//if "type" contains "sushi", then do something instead of alter array
return type.rangeOfString("Sushi") != nil
} else {
return false
}
}
}
You can use the contains function:
func startCheckOptions(objects: [AnyObject]) -> Bool {
return contains(objects as [PFObject]) { (object) -> Bool in
if let type = object["Type"] as? String {
return type.rangeOfString("Sushi") != nil
}
else {
return false
}
}
}
if startCheckOptions(objects) {
println("yes")
}
else {
println("no")
}
This has the advantage of not building a new array containing the matching objects and stopping on the first match.
In this case you'd be better off protecting the objects cast (or really handling one time somewhere else) by casting it to [PFObject] ASAP. Leaving AnyObject references floating around can only lead to confusion and heartache.
filter() does not alter an array, but it returns a new array. What you have above is correct. objects will be the original array, and filteredArray will be the new array consistent of objects where "type" is "sushi".
I want to disable one specific row in datagrid in following manner:
1) Highlight one row with a different color
2) Disable checkbox/radio button selection of that row
3) Disable inline editing of cells present in that row but allow inline editing for other rows.
Pls. help if you have any ideas.
You can use a combination of the following functions to extract stuff
// as example, one of youre items uses identifier:'id' and 'id:10'
var identifier = '10';
var item = store._arrayOfTopLevelItems[10]; // you probably have this allready
var index = grid.getItemIndex(item); // find which index it has in grid
var rowNode = grid.getRowNode(index); // find a DOM element at that index
You will have the <div> as rowNode, it contains a table with cells (as many as you got columns). Set its background-color
The checkbox thing, you will prly know which cell-index it has
var cellNode = dojo.query('td[idx='+cellIndex+']', rowNode)[0];
// with cellType Bool, td contains an input
var checkbox = cellNode.firstChild;
Editing is another store really.. works in focus handlers. To override it, you must keep like an array of rows which you dont want editable (allthough the cell.editable == true).
function inarray(arr, testVal) {
return dojo.some(arr, function(val) { return val == testVal }).length > 0
}
grid.setNonEditable = function (rowIndex) {
if(! inarray(this.nonEditable,rowIndex) )
this.nonEditable.push(rowIndex);
}
grid.setEditable = function (rowIndex) {
this.nonEditable = dojo.filter(this.nonEditable, function(val) { return val != rowIndex; });
}
var originalApply = grid.onApplyEdit
grid.onApplyEdit = function(inValue, inRowIndex) {
if(! inarray(this.nonEditable,inRowIndex) )
originalApply.apply(this, arguments);
}
If you are using dojox.grid.DataGrid you can use canEdit function to disable row editing or cell editing :
grid = new dojox.grid.DataGrid({
canEdit: function(inCell, inRowIndex) {
var item = this.getItem(inRowIndex);
var value = this.store.getValue(item, "name");
return value == null; // allow edit if value is null
}
}