(lord help me for programming in AS2)
i'm itterating thru an array of text field objects and tracing the selected focus field when pressing tab, as well as each object.
i'm trying to equate these object, but while they trace the exact same they are not.
m_InputFieldsArray = new Array(m_TitleTextInput, m_CommentsTextArea, m_EmailTextInput);
for (var i:Number = 0; i < m_InputFieldsArray.length; i++)
{
trace("Get Focus: " + Selection.getFocus());
trace("Arr Index: " + m_InputFieldsArray[i].textField);
if (Selection.getFocus() == m_InputFieldsArray[i].textField)
{
trace("Match!");
return;
}
else
{
trace("NO Match!");
}
}
the output:
Get Focus: _level0.m_Window.form.m_TitleTextInput.textField
Arr Index: _level0.m_Window.form.m_TitleTextInput.textField
NO Match!
Get Focus: _level0.m_Window.form.m_TitleTextInput.textField
Arr Index: _level0.m_Window.form.m_CommentsTextArea.textField
NO Match!
Get Focus: _level0.m_Window.form.m_TitleTextInput.textField
Arr Index: _level0.m_Window.form.m_EmailTextInput.textField
NO Match!
the first group traces the same, but apparently they do not match. Selection.getFocus() returns a string, while the array index is tracing the text field object. if i add toString() to the text field object it will trace as [Object object]
how can i accomplish a match?
Use eval() for the Selection.getFocus()
An alternative, if you don't want to use eval(), that has a bad reputation, to get the same kind of string representation as Selection.getFocus() returns, you can use "" + m_InputFieldsArray[i].textField. It won't return "[Object object]", as toString() does.
That is basically what you see in your trace calls, that a string concatenated with the object reference gives the path to the object, rather than .toString() on the object.
I can't test AS2 right now, but I'm pretty sure that is how it works. So you could do something like this:
if (Selection.getFocus() == "" + m_InputFieldsArray[i].textField)
Related
I have a situation where I have a list that can be at most 4 elements.
However, if I have only 1-3 elements to put in that list, how can I fill the remainder with null values?
For example, a List<int?> of length 4 with 2 given elements, should result in:
[1,3] -> [1,3,null,null]
Here's what I'm doing, but maybe there is a better way
List.generate(4, (index) {
try {
final id = given.elementAt(index);
return id;
} catch (error) {
return null;
}
});
The simplest version would probably be:
[for (var i = 0; i < 4; i++) i < given.length ? given[i] : null]
You can use List.generate, but in this case, the function is simple enough that a list literal can do the same thing more efficiently.
(Or, as #jamesdlin says, if you want a fixed-length list, use List.generate).
A more indirect variant could be:
List<GivenType?>.filled(4, null)..setAll(0, given)
where you create a list of four nulls first, then write the given list into it. It's probably just more complicated and less efficient.
Hello I am new to dart and trying to find an item by property name in a list of list.
class Product{
String id;
String title;
Product(this.id,this.title);
}
void main(){
List<List<Product>> allProdcuts=[
//New Prodcuts
[
Product("1","Hammer"),
Product("3","Nails"),
Product("2","Screws"),
],
futureItems,
//Old Prodcuts
[
Product("4","Rock"),
Product("5","Paper"),
Product("6","Scissor"),
],
//Rare Items
[
Product("7","Plank"),
Product("8","Wires"),
Product("9","Box"),
],
];
print(allProdcuts.where((itemsList)=>itemsList.contains((product)=>product.title='Wires')));
//Returns ()
}
I have tried using for a single List:
List<Product> futureItems= [
Product("101","Galactic Hammer"),
Product("301","Galactic Nails"),
Product("201","Galactic Screws"),
];
print(newProduct.firstWhere((p)=>p.title=='Hammer'));
//Instance of 'Product'
Also tried this:
print(allProdcuts.map((itemList)=>itemList.firstWhere((p)=>p.title=='Nails')));
// Bad state: No elementError: Bad state: No element.
But there is an element with the title='Nails'.I don't understand what I am doing wrong.
You are calling itemList.firstWhere((p)=>p.title=='Nails') on each list, also the ones with no element with title "Nails". Since firstWhere throws if there is no matching value, it does that for two of your three lists. Also, in the example, itemsList.contains(...) does not take a callback, so you are just checking whether a function is in the list, which it isn't. You might want to use any for that, but it won't solve the problem here.
To do this efficiently, I'd probably create helper function:
Product findByTitle(List<List<Product>> allProducts, String title) {
for (var products in allProducts) {
for (var product in products) {
if (product.title == title) return product;
}
}
// Or return `null`.
throw ArgumentError.value(title, "title", "No element with that title");
}
The return in the middle allows you to skip out of the double iteration the moment you have a match, something which is harder to do with firstWhere/map/forEach etc.
One alternative solutions would be:
var product = allProducts.expand((l) => l.where((p) => p.title == title)).first;
which finds all the products with the given title and flattens them into a single iterable, then picks the first one (if there are any). Because iterables are lazy, it will actually stop at the first match.
There are many ways to solve this.
One example is to use the forEach() method:
allProdcuts.forEach(
(List<Product> l)=>l.forEach(
(Product p){
if (p.title=="Nails")
print(p.id);
}
)
);
The for each method receives a function and applies this function to every element on the list. If you have a lists of lists, you can do this twice to get a function applied to each element of the sub lists.
The above code prints 3, which is the desired result.
Another solution would be to flatten the list first, so you can have an easier search later.
print(allProdcuts.any((innerListOfProducts) =>
innerListOfProducts.any((product) => product.title == 'Wires')));
This code will return true if 'Wires' is in the inner list, and false otherwise.
I would like to obtain an object from a List based on a specific search criteria of its member variable
this is the code I am using
class foo
{
foo(this._a);
int _a;
}
List<foo> lst = new List<foo>();
main()
{
foo f = new foo(12);
lst.add(f);
List<foo> result = lst.where( (foo m) {
return m._a == 12;
});
print(result[0]._a);
}
I am getting the error and not sure how to resolve this
Uncaught exception:
TypeError: Instance of 'WhereIterable<foo>': type 'WhereIterable<foo>' is not a subtype of type 'List<foo>'
I am trying to search for an object whose member variable a == 12. Any suggestions on what I might be doing wrong ?
The Iterable.where method returns an iterable of all the members which satisfy your test, not just one, and it's a lazily computed iterable, not a list. You can use lst.where(test).toList() to create a list, but that's overkill if you only need the first element.
You can use lst.firstWhere(test) instead to only return the first element, or you can use lst.where(test).first to do effectively the same thing.
In either case, the code will throw if there is no element matched by the test.
To avoid throwing, you can use var result = lst.firstWhere(test, orElse: () => null) so you get null if there is no such element.
Another alternative is
foo result;
int index = lst.indexWhere(test);
if (index >= 0) result = lst[index];
The answer is simple. Iterable.where returns an Iterable, not a List. AFAIK this is because _WhereIterable does its computations lazily.
If you really need to return a List, call lst.where(...).toList().
Otherwise, you can set result to be an Iterable<foo>, instead of a List<foo>.
or you can go crazy and do this:
bool checkIfProductNotFound(Map<String, Object> trendingProduct) {
bool isNotFound = this
._MyProductList
.where((element) => element["id"] == trendingProduct["id"])
.toList()
.isEmpty;
return isNotFound ;
}
I Use this sample for search in Map but not work :|:
var xmenList = ['4','xmen','4xmen','test'];
var xmenObj = {
'first': '4',
'second': 'xmen',
'fifth': '4xmen',
'author': 'test'
};
print(xmenList.indexOf('4xmen')); // 2
print(xmenObj.indexOf('4xmen')); // ?
but I have error TypeError: xmenObj.indexOf$1 is not a function on last code line.
Pelease help me to search in map object simple way same as indexOf.
I found the answer:
print(xmenObj.values.toList().indexOf('4xmen')); // 2
or this:
var ind = xmenObj.values.toList().indexOf('4xmen') ;
print(xmenObj.keys.toList()[ind]); // fifth
Maps are not indexable by integers, so there is no operation corresponding to indexOf. If you see lists as specialized maps where the keys are always consecutive integers, then the corresponding operation should find the key for a given value.
Maps are not built for that, so iterating through all the keys and values is the only way to get that result.
I'd do that as:
K keyForValue<K, V>(Map<K, V> map, V value) {
for (var entry in map.entries) {
if (entry.value == value) return key;
}
return null;
}
The entries getter is introduced in Dart 2. If you don't have that, then using the map.values.toList().indexOf(value) to get the iteration position, and then map.keys.elementAt(thatIndex) to get the corresponding key.
If you really only want the numerical index, then you can skip that last step.
It's not amazingly efficient (you allocate a new list and copy all the values). Another approach is:
int indexOfValue<V>(Map<Object, V> map, V value) {
int i = 0;
for (var mapValue in map.values) {
if (mapValue == value) return i;
i++;
}
return -1;
}
You can search using .where(...) if you want to find all that match or firstWhere if you assume there can only be one or you only want the first
var found = xmenObj.keys.firstWhere(
(k) => xmenObj[k] == '4xmen', orElse: () => null);
print(xmenObj[found]);
I am trying to iterate over a list of parameters, in a grails controller. when I have a list, longer than one element, like this:
[D4L2DYJlSw, 8OXQWKDDvX]
the following code works fine:
def recipientId = params.email
recipientId.each { test->
System.print(test + "\n")
}
The output being:
A4L2DYJlSw
8OXQWKDDvX
But, if the list only has one item, the output is not the only item, but each letter in the list. for example, if my params list is :
A4L2DYJlSwD
using the same code as above, the output becomes:
A
4
L
2
D
Y
J
l
S
w
can anyone tell me what's going on and what I am doing wrong?
thanks
jason
I run at the same problem a while ago! My solution for that it was
def gameId = params.gameId
def selectedGameList = gameId.class.isArray() ? Game.getAll(gameId as List) : Game.get(gameId);
because in my case I was getting 1 or more game Ids as parameters!
What you can do is the same:
def recipientId = params.email
if(recipientId.class.isArray()){
// smtg
}else{
// smtg
}
Because what is happening here is, as soon as you call '.each' groovy transform that object in a list! and 'String AS LIST' in groovy means char_array of that string!
My guess would be (from what I've seen with groovy elsewhere) is that it is trying to figure out what the type for recipientId should be since you haven't given it one (and it's thus dynamic).
In your first example, groovy decided what got passed to the .each{} closure was a List<String>. The second example, as there is only one String, groovy decides the type should be String and .each{} knows how to iterate over a String too - it just converts it to a char[].
You could simply make recipientId a List<String> I think in this case.
You can also try like this:
def recipientId = params.email instanceof List ? params.email : [params.email]
recipientId.each { test-> System.print(test + "\n") }
It will handle both the cases ..
Grails provides a built-in way to guarantee that a specific parameter is a list, even when only one was submitted. This is actually the preferred way to get a list of items when the number of items may be 0, 1, or more:
def recipientId = params.list("email")
recipientId.each { test->
System.print(test + "\n")
}
The params object will wrap a single item as a list, or return the list if there is more than one.