CODEWITHSUNDEEP
c#pythonrange
opto abhi
opto abhi

Reputation: 317

Enumerable for negative ranges

In python we have a range that can produce for an array with negative integers too.

For example:

In[4]: range(-2, 2+1)
Out[4]: [-2, -1, 0, 1, 2]

Is there an equivalent system in C#; I am aware of IEnumerable method, but upon trying it I get the following output:

//Rextester.Program.Main is the entry point for your code. Don't change it.
//Compiler version 4.0.30319.17929 for Microsoft (R) .NET Framework 4.5

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace Rextester
{
    public class Program
    {
        public static void Main(string[] args)
        {
            //Your code goes here
            Console.WriteLine("Hello, world!");
            int half_window = 2;
            var mySeq1 = Enumerable.Range(-2, 2+1).ToArray();
            foreach(var item in mySeq1)
    Console.Write(item.ToString() + " ");
        } 
    }
}

Produces the output:

Hello, world!
-2 -1 0

Is there already an inbuilt method that I can use to get the python's output ?

Upvotes: 5

Views: 4394

Answers (4)

Saveyy
Saveyy

Reputation: 75

Enumerable.Range works like this

Enumerable.Range(STARTVALUE, How many to count up)

Example Enumerable.Range(6, 10) Would produce

arr[6,7,8,9,10,11,12,13,14,15,16]

that is, 10 elements starting from

If you want to count up to a surden point you'll have to write your own functionality. Something alike 

MakeRange(int st, int end)
{
    var range = st < 0 ? Math.Abs(st) + end + 1 : end-st;

    return Enumerable.Range(st, range);
}

Hope this helped you

Upvotes: 0

RoadieRich
RoadieRich

Reputation: 6566

C#'s Enumerable.Range takes a start value and a count - the number of elements to return, not an end value like in python. To get the equivalent return value to python, you need to call it as:

Enumerable.Range(start, end-start);

So in your case, the call would be

Enumerable.Range(-2, (2+1) - (-2));

which is the same as saying

Enumerable.Range(-2, 5);

The only caveat is you need to be careful that end-start is not negative, otherwise Enumerable.Range will throw an ArgumentOutOfRangeException.

Upvotes: 0

TVOHM
TVOHM

Reputation: 2742

Exactly as cubrr says, the second parameter works slightly differently - if you wanted to write your own method that works exactly like the Python equivalent, you could use:

public static class MyEnumerable
{
    public static IEnumerable<int> Range(int start, int stop)
    {
        for (int i = start; i < stop; i++)
            yield return i;
    }
}

Used as:

var result = MyEnumerable.Range(-2, 3); // -2, -1, 0, 1, 2

Upvotes: 1

cbr
cbr

Reputation: 13652

The second argument of Enumerable.Range specifies the count of the elements to be generated, not the stop value.

Console.WriteLine("Hello, world!");
int half_window = 2;
var mySeq1 = Enumerable.Range(-2, 5).ToArray();
//                                ^
foreach(var item in mySeq1)
    Console.Write(item.ToString() + " ");

Output:

Hello, world!
-2 -1 0 1 2

Upvotes: 9

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