In Java, is there a way to truncate an array without having to make a copy of it? The common idiom is Arrays.copyOf(foo, n) (where the new array is n elements ... |
What is the prefered way to copy an array of a non-primitve type in Java? How about performance issues?
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What is the difference between
System.arraycopy(),clone()- manual copying by iterating through the elements
- and just doing
arraynew = arrayold?
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I would like to know what is the right way to copy two-dimension array from temporary array into original array.
The array size is unknown at the beginning of the program and ... |
I am trying to create a method that pretty much takes anything as a parameter, and returns a concatenated string representation of the value with some delimiter.
public static String getConcatenated(char delim, ...
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I have some library of classes, working with my data, which is being read into buffer. Is it possible somehow to avoid copying arrays again and again, passing parts of data ... |
What is the best way (elegant/efficient) to copy two arrays into a new one ?
Regards,
F
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I have been facing this problem for a while now and it is really starting to frustrate me.
I have an array A which is constantly being updated. Lets say A = ... |
Please tell me how can i copy data from one array to another
public class A {
public static void main(String args[]) {
...
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hello , i am having problem with System.arraycopy() method i am getting NullPointerExceptions with it. What i want to do is just to copy a few elements from one array to another so this method seems convinient for me. I know i can do this by hand myself but if it's there for me why not use it. Here is what ... |
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No. For starters, the second code sample doesn't even compile, so that would be one significant difference. I think I see what it's supposed to do, but I'm always deeply suspicious of code that uses random indentation like that. Why is "myArray[index] = array;" indented in both code samples? Is it supposed to be looped over somehow? Am I correct in ... |
Will you please post the exact error message that you recieve? Copy and paste it word for word so we don't have to guess what the problem is. Also, as Adrian mentioned, the code you posted doesn't even match the description you gave. I don't see any code that is trying to copy from one array to another. The System.out.println() method ... |
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I have an array of exactly 50 integers. I need to search through the array until I find a value of either 49 or 50. As soon as one of these values is found, I want to export all of the values that came before to their own array. Next, I want to go through the original array until the other ... |
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I apologize for no code tags. Well the first loop i believe will increment from the mid-point of the array so it would assign temp2[0]=numbers[4] for example.. As for the second part I thought that might be a problem as well and made a variable to just hold the value before the loop and use that instead. But when i do ... |
I'm trying to write a program that creates 2 objects that are arrays and copies whats in one of them into the other. The program has an integer named how_many that counts the number of indexes that need to be copied into the array. When I run the program I get an array out of bounds exception and none of the ... |
Take a piece of paper and write down the two source arrays and the target array. Mark the source of the first element to copy from and mark the first target element to receive that value. copy elements and move both marks until all the elements of the first array are copied Move to the second array and set a mark ... |
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24. Array copy forums.oracle.com |
If the length of z is (say) 5, then you would copy it into elements 0 to 4 of k and you would then want to start copying x into element 5 of k, but you are starting the copy at element (z.length + 1), which is 6. Just set pos to z.length instead. |
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Both of them do the same thing. No they don't. One creates a separate array instance; the other merely references the original array instance. this.myArray[0] = "Hello"; for example would have very different results between the two scenarios. One would just modify this.myArray[0]; the other would effectively modify both this.myArray[0] and the original myArray[0] to reference the "Hello" string (because both ... |
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Typical pointless micro-optimization, wasting time trying to decide if the source and target are identical, and not even doing that correctly as far as I can see, and loop unrolling that HotSpot will also do much better. Why they picked 7 is an interesting question, but only slightly. Somebody with not enough real work to do. Throw it away. It probably ... |
The first one doesn't copy the array at all. It only copies the reference to the array. The second one produces a shallow copy of the array (i.e. you've got a new array, but the values contained in both arrays are the same). Strings are a bad example for comparing deep vs. shallow copies, because with them you won't have any ... |
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ARRAY COPY DOESN'T WORK. DO NOT ATTEMPT TO USE IT IN YOUR REPLY TO THIS TOPIC. array copy says that you need the same type of object in the arrays. I'm making a method in a class called SUPERARRAYUTIL where this isn't the case. They all extend from a class i made called SUPERARRAY (in javacase caps tho, i just like ... |
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Hi, Say I have a 2 dimensional byte array appendixBlock[10][] & another 1 dimensional byte array, say, tempBytes[]. I do this in the code: String tempString = new String(((String)object).getBytes(), "UTF-16"); byte[] tempBytes = tempString.getBytes(); bytesNum = tempBytes.length; appendixBlock[appendixIndex] = null; for(int x=0; x |
I am writing an accounting system for a class I'm taking at SLU. I need help figuring out the best way to go about copying a 2D array to a temporary 2D array, for eventually copying it back. Here's my flow of commands: 1. copy a single row of a 2D array 2. change that single row (either add a cell ... |
I understand to copy the elements of A into B we could use a for loop. But can somebody explain to me why you can't just go B = A? Does this just cause B to point to A? So how do arrays work exactly? Is it like in C where each element is actually a pointer to the data, or ... |