Type casting an array as element

Hello all,
I'm relatively new to labVIEW and I would like your help with something.
Let us say I have an array of two I16 elements. I would like to type cast it into one single U32 element. In C, I could simple read it as a U32 or use pointers to get away with it, but I don't seem to be able to find a way to do it here.
Cheers,
S

You can, in fact, use the Type Cast function to do this. Alternately, index out the two array elements, then use Join Numbers to merge them.

Similar Messages

Is there a way to type cast an array of strings to numbers and back again?

I'm working on an application where I want to type cast a string like "power supply" into an array of existing numbers. Then sort the existing numbers, and finally convert the casted numbers back into a string so it can be read by the user. In the attachment, you can see my latest attempt with flatten/unflatten data and the 'convert string to byte array'. I can't seem to make this work. Any ideas?
Thanks - Paul
Attachments:
Paul's Temp scan for components.vi ‏56 KB

OK, here's a quickie (LabVIEW 7.0).
Simply get the sort key from the 1D array, then build the table.
Message Edited by altenbach on 10-27-2006 01:34 PM
LabVIEW Champion . Do more with less code and in less time .
Attachments:
SortedTable.png ‏4 KB
SortedTable.vi ‏37 KB

Object array type casting?

Hi. I still can't get the hang of array type casting. Is it possible to type caste an array of objects? I tried the following
LabelledPanel[] comp = (LabelledPanel[])(content.getComponents());
in my program and I got the ClassCastException.
Exception occurred during event dispatching:
java.lang.ClassCastException: [Ljava.awt.Component;
LabelledPanel is a descendent of JPanel and getComponents() supposed to return Component[]

java does support casting with arrays. The following code will work:
String [] strings = new String[] { "1", "2" };
Comparable [] comps = (Comparable[])strings;
Object [] objects = (Object [])strings;That is, you can cast following the normal rules of assignment. You are having problems because your casting violates the normal rules of assignment- you're trying to cast a type into a differnt type that it does not extend or implement.
the toArray() in the Collections API really has nothing to do with casting. That method converts the current Collection into an array of the same type. Since all arrays extend java.lang.Object, it returns the new array as an Object, which you then cast into the specific type.
You may want to read the language guidlines on casting if you are having problems with it:
http://java.sun.com/docs/books/jls/second_edition/html/jIX.fm.html
you can also look at the documenation for Class.isAssignableFrom , which explains casting more briefly.

Type cast array to cluster

Is there any real difference between the 'array to cluster' function and simply type casting to a cluster? The image below shows a simple example. Aside from providing the names of each cluster element, the type cast function automatically sets the cluster size, which is a nice feature when working with a typedef. I am really wondering whether there is any downside to type casting when the array and cluster elements are the same data type.
Thanks in advance.
Solved!
Go to Solution.

Type Cast man knows where I live, so my opinion is biased. When I have to make such a conversion, which is practically never, but not equal to never, then I go with the Type Cast. You hit the biggest points, meaningful labels and the ease of going from six to seven to eleven elements with the Type Def. When I do this conversion it is typically because I need to do some property magic which arrays do not allow (all elements must share properties except value). Creating a control from the Array to Cluster function is let's say a Clusterflop, from the Type Cast, exactly what I am looking for. Besides, that Array to Cluster function obfuscates code, is always left at 9 elements, and otherwise needs to go away, or at least do this:
http://forums.ni.com/t5/LabVIEW-Idea-Exchange/Remove-Default-Behavior-from-Array-To-Cluster/idi-p/17...
First of all, ask yourself if you really should be doing this, if the answer is yes then I say Type Cast.

Splitting and type casting huge string into arrays

Hello,
I'm developing an application which is supposed to read measurement files. Files contain I16 and SGL data which is type casted into string. I16 data is data from analog input and SGL is from CAN-bus data in channel form. CAN and analog data is recorded using same scan rate.
For example, if we have 6 analog channels and 2 CAN channels string will be (A represents analog and C represents CAN):
A1 A2 A3 A4 A5 A6 C1 C2 A1 A2 A3 A4 A5 A6 C1 C2 A1 A2 .... and so on
Anyway, I have problems reading this data fast enough into arrays. Most obvious solution to me was to use shift registers and split string in for loop. I created a for loop with two inner for loops. Number of scans to read from string is wired to N terminal of the outermost loop. Shift register is initialized with string read from file.
First of the inner loops reads analog input data. Number of analog channels is wired to its N terminal. It's using split string to read 2 bytes at a time and then type casts data to I16. Rest of the string is wired to shift register. When every I16 channel from scan is read, rest of the string is passed to shift register of the second for loop.
Second loop is for reading CAN channels. It's similar to first loop except data is read 4 bytes at a time and type casted to SGL. When every CAN channel from scan is read, rest of the string is passed to shift register of the outermost loop. Outputs of type cast functions are tunneled out of loops to produce 2D arrays.
This way reading about 500 KB of data can take for example tens of seconds depending on PC and number of channels. That's way too long as we want to read several megabytes at a time.
I created also an example with one inner loop and all data is type casted to I16. That is extremely fast when compared to two inner loops!
Then I also made a test with two inner loops where I replaced shift register and split string with string subset. That's also faster than two inner loops + shift register, but still not fast enough. Any improvement ideas are highly appreciated. Shift register example attached (LV 7.1)
Thanks in advance,
Jakke Palonen
Attachments:
String to I16 and SGL arrays.vi ‏39 KB

OK, there is clearly room for improvement. I did some timing and my two above suggestions are already about 100x faster than yours. A few teeaks led to a version that is now over 500x faster than the original code.
A few timings on my rather slow computer (1GHz PIII Laptop) are shown on the front panel. For example with 10000 scans (~160kB data as 6+2) my new fastest version (Reshape II) takes 14 ms versus the original 7200ms! It can do 100000 scans (1.6MB data) in under 200 ms and 1000000 scans (15MB data) in under 2 seconds.
I am sure the code could be further improved. I recommend the Reshape II algoritm. It is fastest and can deal with variable channel counts. Modify as needed.
Attached is a LabVIEW 7.1 version of the benchmarking code, containing all algorithms. I have verified that all algorithms produce the same result (with the limitation that the cluster version only works for 6*I16+2*SGL data, of course). Remember that the reshape function is extremely efficient, because it does not move the data in memory. I have some ideas for further improvements, but this should get you going.
Message Edited by altenbach on 08-05-2005 03:06 PM
LabVIEW Champion . Do more with less code and in less time .
Attachments:
StringI16SGLCastingTimer.png ‏48 KB
StringtoI16andSGLArraysMODTimer.vi ‏120 KB

Change element type of an array of containers (from LabVIEW)

Hi,
I have an empty Array of Container type and need to insert an element of a custom data type definition. If I already have an element of the type definition, it is simple to copy that element and insert it as a new element. But inserting a new element to a empty array I need to specify that the element should be of this data type.
Getting the type definition with the Method "GetTypeDefinition" and inserting this as a new value simply "moves" my type definition to the inserted element (which is not suppose to happen). Can't find a method to change data type and seems that none of the property options does the trick to.
I just need to do the same as "change type" in the TestStand editor, just inside LabVIEW.
What did I miss??
Thanks
Note: Use edit of the step in the attached sequence file. Collapse and expand "Locals" after running the Edit function to see the result.
Attachments:
InsertElementInArrayOfContainersOfTypeDef.seq ‏5 KB
InsertArrayElement.vi ‏35 KB

Hi,
When i am writing my stuff i was not able to open your SequenceFile. Now i was.
My upper example is only working for arrays of Types. It is also working on empty Arrays, too.
Please tell me why you do not use an array of types ?
Regards
Juergen
=s=i=g=n=a=t=u=r=e= Click on the Star and see what happens :-) =s=i=g=n=a=t=u=r=e=

Type casting arrays

i m reading an array of int from ObjectOutPutStream. can any body tell how do we type cast an object to array ??

karansha:
I'm sure you mean you're trying to read in an int[] from an ObjectInputStream that was written to an ObjectOutputStream since you can't read from an OutputStream. Use something like this:
ObjectInputStream in = <whatever>;
int[] intArray = (int[])in.readObject();adramolek:
Why should you use an Integer[] instead of an int[] for serialization? All arrays of primitives -- boolean[], byte[], double[], float[], int[], long[], short[] -- are serializable as is; there is no need to convert them to arrays of their wrapper types simply to serialize them.
In fact, the output from the following piece of code shows exactly which interfaces are implements by an int[]:
Class cls = int[].class;
Class[] interfaces = cls.getInterfaces();
for (int i = 0; i < interfaces.length; i++) {
System.out.println(interfaces.getName());
The output is:
java.lang.Cloneable
java.io.SerializableThe output is identical for each of boolean[], byte[], double[], float[], int[], long[], and short[], showing that each type is both serializable [i]and cloneable.
Shaun

How can I check an object is an instance of any type within an array of related types?

In LabVIEW, it's possible to check the runtime type of an object using To More Specific Class.vi. One usage of this would be to perform a safety check if some kind of class uses instances of another kind of class but is only able to handle a subset of that class' child types.
For instance, let's say you had Beverage.lvclass, which represents an abstract type of product, and several subclasses: Coffee.lvclass, Tea.lvclass and Soda.lvclass.
We also have a Person.lvclass which can drink beverages. A person also has preferences about the drinks they do or do not like:
Attached is an implementation of this in LabVIEW.
In Person.lvclass : Drink.vi, I have the following code. For whatever reason the wire appears broken in these snippets but it's all fine in the actual code.
In Scenario.vi, I have the following code:
What I'm finding is that no error is generated and instead I get "Yum, I love tea!", "Yum, I love coffee!" and "Yum, I love soda!". My guess is that To More Specific Class.vi casts to the static type of the "target class" input wire rather than its runtime type - and because I'm passing in elements from an array of types, the wire's static type is upcasted to the most specific type that is a superclass of the types in the array - which would be Beverage.lvclass. And so the cast is trying to determine if an object of static type Beverage.lvclass is an instance of Beverage.lvclass, which will of course be the case all the time.
Is there any way to make LabVIEW check against the most specific runtype type of an object? As in, is there something I could do that, in this example case, would allow me to get the required behaviour of Joe throwing an error when he's made to drink soda? Or is this another limitation of LabVIEW that I'm going to have to live with?
Solved!
Go to Solution.
Attachments:
TypeCastingExample.zip ‏64 KB

tst wrote:
Your guess seems reasonable. I can't check right now, but there's a primitive called preserve run time type, which should do what you want.
Cheers, that seems to have got it! I've never really looked at Preserve Run-Time Class before, but it seems to do the right thing.

Could not type cast in java embedding

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
org.xml.sax.InputSource in = (org.xml.sax.InputSource) getVariableData("Invoke_1_getRoutingAndFrameJumpers_OutputVariable","getRoutingAndFrameJumpersResponse");
Document doc = db.parse(in);
In the above code I am trying to type cast the variable getRoutingAndFrameJumpersResponse into org.xml.sax.InputSource so that i can parse.
I am not getting any error during compilation
but I am unable to type cast some run time error is coming in the line were I am type casting but I am not able to see the runtime error.
How can I see the runtime error in java embedding, how to type cast a variable into xml so that I can parse it.

Hi Arun,
Could you try using the bpelx:rename extension in an assign activity enables a BPEL process to rename an element through use of XSD type casting.
<bpel:assign>
<bpelx:rename elementTo="QName1"? typeCastTo="QName2"?>
<bpelx:target variable="ncname" part="ncname"? query="xpath_str" />
</bpelx:rename>
</bpel:assign>
Cheers
A

Type casting

In my program i get a double array from a function call, i want to convert this into an int array, but when i try to type cast it the compiler tells me they are inconvertible types. ie.
int[][] mat = (int[][])mateng.getArray("arraySig");
where the getArray function returns a double array.
Is there any way around this? I have tried to cast the double[][] into an Object[][] array and then back to an int[][], but the compiler wouldnt let me do this either.
Thanks
Alex

One might ask why you're returning a double[][] if you
actually want a int[][]The method returns a double[][] because its a generic method that will also be used to get double[][]s. In those cases it wont do to lose the information that only returning an int[][] would lose.
I wanted to be able to cast the double[][] to an int[][] when i return a specific matrix (ie a ones matrix or a logical matrix).
Alex

Type casting for properties accessed in COM Object

I have a com object that I need to access which provides my a
list of addresses in an Array. The object give me a property that
has a count for the number of addresses and then I have a loop that
calls the property which contains the address details to get each
individual address each time passing to the property the INDEX
value on the loop.
This errors out each time.
The error I get is
Error casting an object of type to an incompatible type.
This usually indicates a programming error in Java, although it
could also mean you have tried to use a foreign object in a
different way than it was designed.
It appears the the variable type of the index is not
compatible with the property of the component(which is an int).
IS there some way to type cast the variable used as the index
for CFLOOP to that of an INT?

You can try to use the JavaCast("int", myValue) function. It
works great for Java objects, but I'm not sure how well it will
work for COM. Worth a try, I guess.
In your case it would be something like:
<cfobject type="COM" context="INPROC" action="create"
name="MR" class="DLLNAME">
<cfloop from="1" to="#AddressCount#" index="i">
<cfset VDname = mr.vdsname(JavaCast("int", i))>
<cfset VDaddress = mr.vdsaddress(JavaCast("int", i))#>
<cfset VDXML = mr.VDSXML(JavaCast("int", i))>
</cfloop>

Type casting in JAX-RPC

Hello
I was trying to do a JAX-RPC application, and I had some problems with type casting. My application worked fine with primitive types, vectors of primitive types, and beans with primitive type properties. But it didn't work with vectors of beans, or ArrayList's of beans... It couldn't deserialize the result on client side... Can anyone help?
The Java Web Services Tutorial says that JAX-RPC supports beans and vectors, but I had the impression that this is not a "recursive" support, like "beans with vectors" or "vectors of beans"... Does it make sense?
By the way, I was using a DII client...
Thanks,
Alexandre Murakami

Hello!
Thanks for the reply! I can't put the code of my application here (because it's quite big and it's from work)... But I followed the dii client example from the Web Services Tutorial...
I'm trying to do a kind of a general client... The parameters are the URL of the service, the name of the operation, a list of parameters and the return type class.. And it takes the rest of the service information from the WSDL file... About the return type, I take the QName of the return type from the WSDL:
<message>
<part name="result" type="...">...
then I call the call.setReturnType(QName, Class) method. The return type was an array of a very simple bean, something like:
class Person {
String name;
int age;
public String getName() {...}
public void setName(...) {...}
public int getAge() {...}
public void setAge(...) {...}
I don't know if the information I put here is enough... but anyway, thanks for the reply!
Alexandre Murakami

I need To Understand the "Type Cast Function"

Dears,
I need To Understand How the "Type Cast Function" Work, and if you can Give me an Example it will be Apperciated
BR
Ahmed

In its simplest explanation Type Cast allows you to reinterpret a series of bytes. The numeric conversion functions convert from one data type to another and essentially do the same thing that Type Cast does, albeit with just numbers. Type Cast allows you to extend this to convert one data type to another, beyond just numbers. Thus, you could convert an array of 2 U8 values into a single U16 number by using Type Cast like this:
or you could reinterpret an array of lots of U8 values into an array of U16 values like this:
How you use it is entirely up to you, but it is an extremely powerful function. What are you trying to do?
Attachments:
Example_VI.png ‏6 KB
Example2_VI.png ‏11 KB

CASTING AN ARRAY OF OBJECTS

Hi guys, How I need do to cast an array of objects to a String array??!?!
I am using
String array[] = (String[]) getObjects();
//getObjects() return a Object[]Thanks.
Giscard

And what? You get a ClassCastException? If so, you're attempting to change the type of reference that points to the object to a type that isn't the same as the class of the object instance, or a class that the class of the object instance extends, or an interface that the class of the object instance implements.

How to cast an array object to array of string

* Can someone please tell me why SECTION 3 causes a cast
* exception?
* What I am really trying to do is put Strings into a vector and
* return them as an array of String with a line like:
*     return (String[])myVector.toArray();
* How to do this?
* Thank You!
public class CastArrayTest
     public static void main(String args[]){
          //SECTION 1: This works
          String[] fruits = {"apple", "banana"};
          Object[] objs = (Object[])fruits;
          String[] foods = (String[])objs;
          for (int i = 0 ; i < foods.length ; i++){
               System.out.println(foods);
          //SECTION 2: this works too
          Object anObj = new Object();
          String aString = "ok";
          anObj = aString;
          String anotherString = (String)anObj;
          System.out.println("word for single obj is " + anotherString);
          //SECTION 3: this causes cast exception at line
          // String[] strings = (String[])stuff
          Object[] stuff = new Object[2];
          String a = "try";
          String b = "this";
          stuff[0] = a;
          stuff[1] = b;
          String[] strings = (String[])stuff;
          for (int x = 0 ; x < strings.length ; x++){
               String s = strings[x];
               System.out.println("the string is " + strings[x]);

I understand all replies so far, but from my
understanding, objects are passed by reference No, they're not. Rather, object references are passed by value.
Object obj = new Object();
String a = "pass me by reference";
Object anotherObj = (Object)a; // this explicit cast is not necessary
String anotherString = (String)anotherObj; // this cast works because the object in question is a String
There's no passing in that code, so I'm not sure where that even came from. However, that works because it's all legal casting.
works as I think it should, and does, and futhermore
String[] cast to Obj[] cast to String[] works also...Because the object you're casting actually is a String[].
so why not if Obj[] to String[] Because String[] is not a subclass of Object[]. That's just how the language is specified.
futhermore if they are
all string...Again, this has no bearing on the type of the array object.
I saw hot to cast array to String[] and wondered if
this is real cast or calls the toString method...It's a real cast.
but most importantly, does this mean if I have a
vector of Strings and want to get them as an array of
strings, I have to loop through the Obj[] (or vector)
and cast each to (String)...just to get them as an
array of String[]....No, zparticle's code can do that.

Type casting an array as element

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