Lets say I have
int[] arraySegment1 = new int[10];
int[] arraySegment2 = new int[10];
Is there anyway to pass them into a one dimensional array by reference?
int[] array = new int[21];
//Could I now make the arraySegment1 be passed in array[0] - array[10] by reference?
//And arraySegment2 in array[11] - array[21] passed by reference?
//Then when executing:
array[0] = 10000000;
System.Console.WriteLine(arraySegment1[0]);
//It should display 10000000
//By putting the arraySegment1 as reference in the one dimensional array: array?
Checkout the Array.Copy method which allows you to copy segments of arrays to a destination array:
int[] arraySegment1 = new int[10];
int[] arraySegment2 = new int[10];
// TODO: populate the arraySegment1 and arraySegment2 with some values
int[] array = new int[20];
Array.Copy(arraySegment1, 0, array, 0, arraySegment1.Length);
Array.Copy(arraySegment2, 0, array, arraySegment1.Length, arraySegment2.Length);
Also 20 is enough of a Length for the resulting array, not 21 if the 2 source arrays are 10 each.
Try this one..
int[] arraySegment1 = new int[10];
int[] arraySegment2 = new int[10];
int[] array = new int[21];
arraySegment1.CopyTo(array,0);
arraySegment2.CopyTo(array,(arraySegment1.Length));
No. It's not possible with standart arrays. But with generics you can do something like this:
int[] arraySegment1 = new int[10];
int[] arraySegment2 = new int[10];
// populate arrays
List<int[]> lists = new List<int[]>();
lists.Add(arraySegment1);
lists.Add(arraySegment2);
lists[0][0] = 100000;
System.Console.WriteLine(arraySegment1[0]); // then it will display 100000
you typing wrong object
change the arraySegment1 in the write line to be array
System.Console.WriteLine(array[0]);
Related
I want to initialize an array of arrays like in java:
int[][] arrPos=new int[16][48];
int[][] arrPosOther=new int[16][48];
and I can set a row array value like this:
arrPos[0]=arrPosOther[0];
and I can set a cell value like this:
arrPos[1][0]=125;
but in C#, I can declare only like this:
int[][] arrPos=new int[16][];
can not set the column value in the initialization.
It seems like you are trying to find a way to initialize Jagged array in c#: please refer to the following example:
int[][] jaggedArray2 = new int[][]
{
new int[] {1,3,5,7,9},
new int[] {0,2,4,6},
new int[] {11,22}
};
The short form for the same sample is shown below:
int[][] jaggedArray2 =
{
new int[] {1,3,5,7,9},
new int[] {0,2,4,6},
new int[] {11,22}
};
You can also perform the initialization in several steps:
int[][] jaggedArray = new int[3][];
jaggedArray[0] = new int[5];
jaggedArray[1] = new int[4];
jaggedArray[2] = new int[2];
jaggedArray[0] = new int[] { 1, 3, 5, 7, 9 };
jaggedArray[1] = new int[] { 0, 2, 4, 6 };
jaggedArray[2] = new int[] { 11, 22 };
And, apparently, you can implement a sort of for or foreach loop in order to populate the array from some data structure. More reading available at: http://msdn.microsoft.com/en-us/library/2s05feca.aspx
Also, you should probably consider a use of multidimensional array, like int[,] (the C# syntax in this case is different from Java lang).
Hope this will help.
There is no syntax you are looking for.
One statement option could be
int[][] arrPos = Enumerable.Range(0, length).Select(_ => new int[length]).ToArray();
I have the following array:
int[] numbers;
Is there a good way to add a number to the array? I didn't find an extension method that concats 2 arrays, I wanted to do something like:
numbers = numbers.Concat(new[] { valueToAdd });
To concatenate 2 ararys look at: How do I concatenate two arrays in C#?
The best solution I can suggest is to simply use
List<int> numbers
And when needed call the ToArray() extension method (and not the opposite).
you can try this..
var z = new int[x.length + y.length];
x.CopyTo(z, 0);
y.CopyTo(z, x.length);
or
List<int> list = new List<int>();
list.AddRange(x);
list.AddRange(y);
int[] z = list.ToArray();
or
int[] array1 = { 1, 3, 5 };
int[] array2 = { 0, 2, 4 };
// Concat array1 and array2.
var result1 = array1.Concat(array2);
for (int i = 0; i < People.Length; i++) {
People[i] = new Person(first[i], last[i], birth[i]);
}
Now first and last contain 20 strings and birth is a DateTime object that again populates the array people with 20 birthdates. I just need to know how to correctly initialize my array.
You have to use Jagged Array
ex:
You can initialize jagged arrays like this example:
int[][] numbers = new int[2][] { new int[] {2,3,4}, new int[] {5,6,7,8,9} };
You can also omit the size of the first array, like this:
int[][] numbers = new int[][] { new int[] {2,3,4}, new int[] {5,6,7,8,9} };
You initialize your array with the desired size:
Person[] people = new Person[20];
To automatically use the length of, for example, first:
Person[] people = new Person[first.Length];
I am trying to do 2 different sorting algorithms on 2 exactly similar arrays (numbers and numbers2) that are generated through the Random class. I declare my 2 arrays and fill them with Random.NextBytes.
After that I do my first algorithm on numbers and then my second sorts on numbers2.
But I notice that numbers2 just seems to be a pointer to numbers because by the time I want to sort numbers2 it is already sorted.
How do I fill numbers2 with exactly the same numbers as numbers? Do I need to do it by hand with a for loop? Thank you!
class FillArray
{
public byte[] numbers;
public byte[] numbers2;
//instantiate MS Random object
Random Generator = new Random();
//Constructor which takes array size
public FillArray(int amountx)
{
numbers = new byte[amountx]
Generator.NextBytes(numbers);
numbers2 = new byte[amountx];
numbers2 = numbers;
amount = amountx;
}
Arrays are reference types, so if you want to clone the array you'll need to copy it via Array.Copy.
int[] first = new int[] { 1, 2, 3, 4, 5 };
int[] second = new int[first.Length];
Array.Copy( first, second, first.Length );
first[0] = 10;
// prints 10
Console.WriteLine( first[0] );
// prints 1
Console.WriteLine( second[0] );
You can also use Array.CopyTo. If you don't have a pre-existing array you can use the Clone() method as well to create a new one with shallow copies of all elements.
try
numbers2 = (byte[])numbers.Clone();
instead of
numbers2 = new byte[amountx];
numbers2 = numbers;
use Array.Copy method: Array.Copy Method
int[] source = new int[5];
source[0] = 1;
source[1] = 2;
source[2] = 3;
source[3] = 4;
source[4] = 5;
int[] target = new int[5];
Array.Copy(source, target, 5);
You are assigning the reference for numbers to numbers2 instead of the values. Try this:
public FillArray(int amountx)
{
numbers = new byte[amountx]
Generator.NextBytes(numbers);
numbers2 = new byte[amountx];
Array.Copy(numbers, numbers2, amountx);
amount = amountx;
}
As Ed says, arrays are reference types. Your error is below:
public FillArray(int amountx)
{
numbers = new byte[amountx]
Generator.NextBytes(numbers);
numbers2 = new byte[amountx];
numbers2 = numbers; // this line is why the arrays are the same
amount = amountx;
}
However, I have a different solution than the other 2 presented. If you include the System.Linq namespace, you can use .ToList() and .ToArray():
public FillArray(int amountx)
{
numbers = new byte[amountx]
Generator.NextBytes(numbers);
numbers2 = numbers.ToList().ToArray();
amount = amountx;
}
You will then have 2 separate copies of the array to sort independently.
Since arrays are reference types, you will need to create a clone of the array:
class FillArray
{
public byte[] numbers;
public byte[] numbers2;
//instantiate MS Random object
Random Generator = new Random();
//Constructor which takes array size
public FillArray(int amountx)
{
numbers = new byte[amountx]
Generator.NextBytes(numbers);
numbers2 = new byte[amountx];
// Array Copy solution
Array.CopyTo(numbers2, 0);
// Or a LINQ solution
numbers2 = numbers.ToArray();
// Or a Clone solution
numbers2 = (byte[])numbers.Clone();
amount = amountx;
}
}
How can I copy an array of values to a destination array starting from a specific index without looping?
For example,if I have an array with 2 values, I have to copy those two elements to another array which has a capacity of 5 starting from index 3?
double[] source = new double[] {1, 2};
double[] destination = new double[5]{0,0,0,0,0};
//How to perform this copy?
double[] result = new double[5] {0, 0, 0, 1, 2};
Is this what you're looking for?
Array.Copy(source, 0 /*start loc*/, destination, 3 /*start loc*/, 2 /*count*/);
Use Array.CopyTo or the static method Array.Copy.
source.CopyTo(destination, 3);
double[] source = new double[] {1, 2};
double[] destination = new double[5]{0,0,0,0,0};
//How to perform this copy?
ArrayList result = new ArrayList();
result.AddRange(source);
result.AddRange(destination);
destination = result.ToArray();