I want program a struct in Matlab for saving some parameters.
The struct's name has to change every iteration in a loop, thus in each iteration I make a new struct. Therefore I want something like this:
index={'01','02','03'};
letter={'aa','bb','cc'};
names={'Peter','John','Michael'};
for(i=1:numel(index)){
......
strcat(str, index{i}, letter{i})(i).name = names{i};
}
Then, when the loop has finished I have 3 structs with the next names:
- str01aa{
name = 'Peter'
}
- str02bb{
name = 'John'
}
- str03cc{
name = 'Michael'
}
My problem is that the strcat function with the bracket (i) is not good defined, and the structs are not created.
I hope you can help me.
Thanks.
strcat(str, index{i}, letter{i})(i).name isn't a valid operation, because strcat returns a sting object, which can't possess fields. You need to make that string into a variable name using genvarname (documentation), like so:
index={'01','02','03'};
letter={'aa','bb','cc'};
names={'Peter','John','Michael'};
for(i = 1:numel(index))
{
......
genvarname(strcat('str', index{i}, letter{i}))(i).name = names{i};
}
Note that I changed str to 'str' for consistency with your example. As a general rule, dynamically constructed variable names are bad practice because they make debugging a nightmare.
Let me make a suggestion; instead of having a bunch of structs with different, seemingly arbitrary names, why not try something like this:
index={'01','02','03'};
letter={'aa','bb','cc'};
names={'Peter','John','Michael'};
for(i = 1:numel(index))
{
......
yourStruct(i).id = strcat('str', index{i}, letter{i});
yourStruct(i).name = names{i};
}
Either way, good luck!
Related
With arrays you can use a subscript to access Array Elements directly. You can read or write to them. With Sets I am not sure of a way to write its Elements.
For example, if I access a set element matching a condition I'm only able to read the element. It is passed by copy and I can't therefore write to the original.
For example:
columns.first(
where: {
$0.header.last == Character(String(i))
}
)?.cells.append(value: addValue)
// ERROR: Cannot use mutating member on immutable value: function call returns immutable value
You can't just change things inside a set, because of how a (hash) set works. Changing them would possibly change their hash value, making the set into an invalid state.
Therefore, you would have to take the thing you want to change out of the set, change it, then put it back.
if var thing = columns.first(
where: {
$0.header.last == Character(String(i))
}) {
columns.remove(thing)
thing.cells.append(value: addValue)
columns.insert(thing)
}
If the == operator on Column doesn't care about cells (i.e. adding cells to a column doesn't suddenly make two originally equal columns unequal and vice versa), then you could use update instead:
if var thing = columns.first(
where: {
$0.header.last == Character(String(i))
}) {
thing.cells.append(value: addValue)
columns.update(thing)
}
As you can see, it's quite a lot of work, so maybe sets aren't a suitable data structure to use in this situation. Have you considered using an array instead? :)
private var _columns: [Column]
public var columns : [Column] {
get { _columns }
set { _columns = Array(Set(newValue)) }
// or any other way to remove duplicate as described here: https://stackoverflow.com/questions/25738817/removing-duplicate-elements-from-an-array-in-swift
}
You are getting the error because columns might be a set of struct. So columns.first will give you an immutable value. If you were to use a class, you will get a mutable result from columns.first and your code will work as expected.
Otherwise, you will have to do as explained by #Sweeper in his answer.
I've searched a lot but can't find a clear answer anywhere for string list -> enum.
I've got a list of strings that I want to turn into an enum that I can select from in Unity inspector.
Specifically, I'm trying to make an enum list of all the currently set-up Input buttons from project settings. I've got all the names, just don't know how to make it an enum or similar. Ideally showing up like a KeyCode variable in inspector.
Currently trying (and failing) with:
foreach (string s in names)
{
if (Enum.TryParse(s, true, out list))
Debug.Log(list);
else Debug.Log("FAILED");
}
"names" = static List<string> names;
"list" = static MyList list;
"MyList" = enum MyList { Null }
Returns "FAILED" 58 times for only 29 Input axis.
I want a simple solution, so if its not possible or relatively simple, I'll work out something else.
Code for getting the "names" list of strings (Works correctly):
var inputManager = AssetDatabase.LoadAllAssetsAtPath("ProjectSettings/InputManager.asset")[0];
SerializedObject obj = new SerializedObject(inputManager);
SerializedProperty axisArray = obj.FindProperty("m_Axes");
if (axisArray.arraySize == 0)
Debug.Log("No Axes");
for (int i = 0; i < axisArray.arraySize; ++i)
{
var axis = axisArray.GetArrayElementAtIndex(i);
var name = axis.FindPropertyRelative("m_Name").stringValue;
names.Add(name);
}
Normally you can do
foreach (string colorName in Enum.GetNames(typeof(Colors))) which will iterate the names of the enums.
In your code above you havent shown what list is, nor where names has come from. However.
enum Things
{
Item1 = 0,
Item2 = 1
}
You can get the name from string name = Enum.GetName(typeof(Things), (int)Things.Item2) and you can get values from names with int value = (int)Enum.Parse(typeof(Things), nameOfThing)
So depending on what you actually want in a list and what you start with, iterate through and pick the relevant one
I ended up making my own solution, since (and please correct me if I'm wrong) the TryParse() and Parse() methods appear to need the enum to already contain entries with the same name (or index int) as the string to parse. This defeats the purpose for me, since I am doing this because I don't have the names in there already.
My solution ended up being to switch to having a single string input variable instead of an enum, then use Odin Inspector's ValidateInput attribute to check (for spelling errors, and) if the input variable matches any of the string entries in my dynamic list of InputManager input names (which I update manually using Odin Inspector's Button attribute and the code in the original post).
It's slightly less clean than I wanted, but does the job, so I'm satisfied.
I get an error when I put the type and size of an array of classes
I have tried:
fun main(args :Array<String>) {
class modul() {
var nommodul: String? = null
var coeff: Int? = null
var note: Int? = null
}
var releve
class notes() {
var releve: array<modul>(10){""} here the erreur
}
}
First of all, your code has several errors. This might be an MCVE and/or copy-paste issue, but I need to address these before I get started on the arrays.
var releve before the notes class isn't allowed. You don't assign it, you don't declare a type, and the compiler will complain if you copy-paste the code from your question.
Second, the array var itself: Array is upper-case, and initialization is separate. This would be more valid (note that this still does not work - the solution for that comes later in this answer):
var releve: Array<modul> = Array(10) {...}
// or
var releve = Array<modul>(10) {...}
And the last thing before I start on the array itself: please read the language conventions, especially the naming ones. Your classes should all start with an upper-case letter.
Kotlin arrays are quite different from Java arrays in many ways, but the most notable one being that direct array initialization also requires an initializer.
The brackets are expected to create a new instance, which you don't. You create a String, which isn't, in your case, a modul.
There are several ways to fix this depending on how you want to do this.
If you have instances you want to add to the array, you can use arrayOf:
arrayOf(modulInstance, modulInstance2, ...)
If you want to create them directly, you can use your approach:
var releve = Array(10) { modul() }
A note about both of these: because of the initialization, you get automatic type inference and don't need to explicitly declare <modul>
If you want Java-style arrays, you need an array of nulls.
There's two ways to do this:
var releve = arrayOfNulls<modul>(10)
// or
var releve = Array<modul?>(10) { null }
I highly recommend the first one, because it's cleaner. I'm not sure if there's a difference performance-wise though.
Note that this does infer a nullable type to the array, but it lets you work with arrays in a similar way to Java. Initialization from this point is just like Java: releve[i] = modul(). This approach is mostly useful if you have arguments you want to add to each of the classes and you need to do so manually. Using the manual initializers also provides you with an index (see the documentation) which you can use while initializing.
Note that if you're using a for loop to initialize, you can use Array(10) { YourClass() } as well, and use the supplied index if you need any index-sensitive information, such as function arguments. There's of course nothing wrong with using a for loop, but it can be cleaner.
Further reading
Array
Lambdas
here some example of kotlin array initialization:
array of Library Method
val strings = arrayOf("January", "February", "March")
Primitive Arrays
val numbers: IntArray = intArrayOf(10, 20, 30, 40, 50)
Late Initialization with Indices
val array = arrayOfNulls<Number>(5)
for (i in array.indices) {
array[i] = i * i
}
See Kotlin - Basic Types for details
Given the input value:
input =
name:'Foo'
id:'d4cbd9ed-fabc-11e6-83e6-307bd8cc75e3'
ref:5
addtData:'d4cbd9ed-fabc-11e6-83e6-307bd8cc75e3'
data:'bar'
When I try to destructure the input via a function like this:
simplify: (input)->
{ name, ref, id } = input
...the return value is still the full input or a copy of the input.
Am I missing something simple here? How can I access the destructured value. If you can't access the value via a return, it seems that destructuring has little value outside of locally scoped values.
While this isn't necessarily an advantage, the only way I was able to transpile and get the correct answer was to assign the destructure values to the local scope using # (aka this).
input =
name:'foo'
data:'bar'
id: 12314
key:'children'
ref:1
f = (input)->
{ #name, #id } = input
r = {}
f.call(r, input)
console.log r # Object {name: "foo", id: 12314}
working example - link
If someone has a better way to approach this, please add an answer so I can select it as this doesn't seem like the best way.
I'm working with treeviews in Powershell - I have a different node for each of our buildings. In my code I'm grabbing variables, Joining them together, and using that as the variable name - but my code is seeing the variable as a string instead of the name of a node that already exists... so I'm getting
You cannot call a method on a null-valued expression.
How can I do this? It would save me from hard-coding in every floor in every building. Here's what my code looks like:
$bldg = "SG1-1" //for example
function refreshPrinterList ( $bldg )
{
$bldg1 = $bldg.substring(0,3)
$floor = $bldg.substring(4,1)
$refreshNode = -join('$TreeNode_',$bldg1,'_',$floor)
$refreshNode.gettype() //Returns System.String`
if($bldg1 -eq "SG1") {
if($floor -eq "1") {
$count = $refreshNode.Nodes.Count
while($refreshNode.Nodes.Count -gt 0)
{
$refreshNode.Nodes.RemoveAt($count)
$count--
}
The -join operator is for strings, and dutifully gives you one back instead of a TreeNode that you want. If you are passing in a string ($bldg looks like a string from your example), then you can do all the string manipulation you want, but there is no TreeNode object in that function to assign a name to. So, we need to make a TreeNode that your function could use. What about something like this?
$newNodeName = -join('$TreeNode_',$bldg1,'_',$floor)
$refreshNode = New-Object System.Windows.Forms.TreeNode($newNodeName )
// do stuff with $refreshNode as it is a TreeNode object like you expect
This $refreshNode will have no Nodes inside of it since we just fabbed it up. Since it looks like you want to modify an existing TreeNode object, pass in the $refreshNode as an argument then modify its friendly description with the $newNodeName.
I was pointed in the right direction over on the Technet Social forum
My question on Technet
The answer was using 'Get-Variable'
I had the two variables $bldg1 and $floor which I joined into a string:
$newNodeName = -join('TreeNode_',$bldg1,'_',$floor)
and then I passed that using 'Get-Variable' - but I had to put the variable name within parantheses, like so:
$refreshNode = (Get-Variable ($newNodeName)).Value
Now, instead of returning a string type it returns my existing string!