Convert String to Int Array Using Linq

Convert string to int array using LINQ

This post asked a similar question and used LINQ to solve it, maybe it will help you out too.

string s1 = "1;2;3;4;5;6;7;8;9;10;11;12";
int[] ia = s1.Split(';').Select(n => Convert.ToInt32(n)).ToArray();

Convert string[] to int[] in one line of code using LINQ

Given an array you can use the Array.ConvertAll method:

int[] myInts = Array.ConvertAll(arr, s => int.Parse(s));

Thanks to Marc Gravell for pointing out that the lambda can be omitted, yielding a shorter version shown below:

int[] myInts = Array.ConvertAll(arr, int.Parse);

A LINQ solution is similar, except you would need the extra ToArray call to get an array:

int[] myInts = arr.Select(int.Parse).ToArray();

How to Convert a String into Integer Array in C#

Try this,

static void Main(string[] args)
{
    int[] num;
    int accum = 0;
    string input = Console.ReadLine();

    num = Array.ConvertAll(input.Split(','), int.Parse);

    for (int i = 0; i < num.Length; i++)
        accum ^= num[i];
    Console.WriteLine(accum);

}

Or by using Linq, just replace as follows, and you should need to use System.Linq namespace.

num = input.Split(',').Select(int.Parse).ToArray();

.NetFiddle : https://dotnetfiddle.net/bahpg9

C# LINQ: How is string([1, 2, 3]) parsed as an array?

The order is the order that you specify. So input.Skip(2) skips the first two strings in the array, so only the last remains which is 3. That can be parsed to an int. If you remove the Skip(2) you are trying to parse all of them. That doesn't work because the commas are still there. You have splitted by white-spaces but not removed the commas.

You could use line.Trim('[', ']').Split(','); and int.TryParse:

string line = "[1, 2, 3]";
string[] input = line.Trim('[', ']').Split(',');
int i = 0;
int[] num = input.Where(s => int.TryParse(s, out i)) // you could use s.Trim but the spaces don't hurt
                 .Select(s => i)
                 .ToArray(); 

Just to clarify, i have used int.TryParse only to make sure that you don't get an exception if the input contains invalid data. It doesn't fix anything. It would also work with int.Parse.

Update: as has been proved by Eric Lippert in the comment section using int.TryParse in a LINQ query can be harmful. So it's better to use a helper method that encapsulates int.TryParse and returns a Nullable<int>. So an extension like this:

public static int? TryGetInt32(this string item)
{
    int i;
    bool success = int.TryParse(item, out i);
    return success ? (int?)i : (int?)null;
}

Now you can use it in a LINQ query in this way:

string line = "[1, 2, 3]";
string[] input = line.Trim('[', ']').Split(',');
int[] num = input.Select(s => s.TryGetInt32())
                 .Where(n => n.HasValue)
                 .Select(n=> n.Value)
                 .ToArray();

Linq OrderBy issue when converting string to int with space

you can avoid empty strings by first filtering them out. i.e.

objStudentList = objStudentList.Where(a => !string.IsNullOrEmpty(a.Pincode))
                               .OrderBy(a => int.Parse(a.Pincode)).ToList();

However, if you want to keep the Student objects that have an empty string but rather replace their Pincode property with "0" you can try this:

objStudentList = objStudentList.OrderBy(a => string.IsNullOrEmpty(a.Pincode) ? int.Parse("0") : int.Parse(a.Pincode))
                               .ToList();

Sum any strings that are numbers from string array using LINQ

You can not combine Where and Select, but you can change it to parse string only once

var sum = array
    .Select(text => (IsNumber: int.TryParse(text, out var number), Number: number))
    .Where(value => value.IsNumber)
    .Sum(value => value.Number);

Another approach to do everything in the Sum

var sum = array.Sum(text => int.TryParse(text, out var number) ? number : 0);

Actually you can unite the Where and Select clauses, only because you calculating a sum.

For text, which is not valid number return 0.

var sum = array
    .Select(text => { int.TryParse(text, out var number); return number; })
    .Sum();

You can go further and create an extension method for string. Which will make such expressions simpler

public static int ParseOrDefault(string value)
{
    int.TryParse(text, out var number); 
    return number;
}

var sum = array.Sum(value => value.ParseOrDefault());

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