CODEWITHSUNDEEP
c#.netarraysstringlinq
Dale Addison
Dale Addison

Reputation: 59

Converting a string array to an integer array

I am reading a text file using C#.Net v3.5 express 2010 containing integers in the format

18 11 2 18 3 14 1 0 1 3 22 15 0 6 8 23 18 1 3 4 10 15 24 17 17 16 18 10 17 18 23 17 11 19

by

string[] code = System.IO.File.ReadAllLines(@"C:\randoms\randnum.txt");

i then placethis into a string by

string s1 = Convert.ToString(code);

And need to be able to read this into an int array for some mathematical processing.

I've tried everything suggested on this site under other posts on this topic, including parsing, and covert array but once I attempt this I get the dreaded "input string is not in a correct format" message

Upvotes: 2

Views: 680

Answers (5)

Rufus L
Rufus L

Reputation: 37070

Some of these answers are great, but if your file contains any strings that can't be converted to an int, int.Parse() will throw an exception.

Although slightly more expensive, consider doing a TryParse instead. This gives you some Exception handling:

int tmp = 0; // Used to hold the int if TryParse succeeds

int[] intsFromFile = System.IO.File
        .ReadAllText(@"C:\randoms\randnum.txt")
        .Split(null)
        .Where(i => int.TryParse(i, out tmp))
        .Select(i => tmp)
        .ToArray();

Upvotes: 2

Hamid Pourjam
Hamid Pourjam

Reputation: 20764

var intArray =  File.ReadAllText(@"C:\randoms\randnum.txt")
        .Split((char[]) null, StringSplitOptions.RemoveEmptyEntries)
        .Select(int.Parse).ToArray();

Upvotes: 2

Nicholas Carey
Nicholas Carey

Reputation: 74365

It's a one-liner, really. This will give you a 1-dimensional array of integers in the file:

private static rxInteger rxInteger = new Regex(@"-?\d+") ;

...

int[] myIntegers1 = rxInteger
                    .Matches( File.ReadAllText(@"C:\foo\bar\bazbat") )
                    .Cast<Match>()
                    .Select( m => int.Parse(m.Value) )
                    .ToArray()
                    ;

If you want it to be a 2-dimensional ragged array, it's not much more complicated:

int[][] myIntegers2 = File
                      .ReadAllLines( @"C:\foo\bar\bazbat" )
                      .Select( s =>
                        rxInteger
                        .Matches(s)
                        .Cast<Match>()
                        .Select( m => int.Parse(m.Value) )
                        .ToArray()
                      )
                      .ToArray()
                      ;

[implementation of validation and error handling left as an exercise for the reader]

Upvotes: 0

Jonesopolis
Jonesopolis

Reputation: 25370

you can use LINQ:

var ints = code.SelectMany(s => s.Split(' ')).Select(int.Parse).ToList();

This will take your list of space-separated numbers and flatten them into a one-dimensional List of ints

Upvotes: 2

MikeH
MikeH

Reputation: 4395

At first glance, it appears the problem is that you're reading in numbers using ReadAllLines. This will return an array of strings where each string represents one line in your file. In your example it appears that your numbers are all on one line. You could use System.IO.File.ReadAllText to get a single string. Then use .Split(new char[]{}, StringSplitOptions.RemoveEmptyEntries); to get the array of strings your looking for.

string allTheText = System.IO.File.ReadAllText(@"C:\randoms\randnum.txt");
string[] numbers = allTheText.Split(new char[]{}, StringSplitOptions.RemoveEmptyEntries);

Upvotes: -1

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