Iterating through a List that is filled with arrays in C#

Question

        public List<string[]> parseCSV(string path)
    {
        List<string[]> parsedData = new List<string[]>();

        try
        {
            using (StreamReader readFile = new StreamReader(path))
            {
                string line;
                string[] row;
                while ((line = readFile.ReadLine()) != null)
                {
                    row = line.Split(',');
                    parsedData.Add(row);
                }
            }
        }
        catch (Exception e)
        {
            MessageBox.Show(e.Message);
        }

        return parsedData;
    }

I want to use this code to parse a CSV, and this returns a List filled with arrays. My question is how do I iterate through the arrays within the list if they are of unknown size?

for example:

for (int a=0; a<=CSVList(firstindex).Length;a++)
         for (int a=0; a<=CSVList(secondindex).Length;a++)

Something like this would read the first index of the CSVList and then the first array element in it...I think I am just really stuck on the syntax.

Thank you

Reed Copsey · Accepted Answer · 2011-02-25 20:34:39Z

5

You can use LINQ to flatten this out, if you just want to write out each value:

var results = parseCSV(path);

foreach(var str in results.SelectMany(i => i))
{
    Console.WriteLine(str);
}

Otherwise, you can do this in two loops:

var results = parseCSV(path);
foreach(var arr in results)
{
    for (int i=0;i<arr.Length;++i) // Loop through array
    {
        string value = arr[i]; // This is the array element...
    }
}

answered Feb 25, 2011 at 20:34

Reed Copsey

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Comments

JaredPar · Accepted Answer · 2011-02-25 20:35:08Z

2

If it's just a List<string[]> values then the simplest syntax is nested foreach loops.

foreach (var arrayElement in CSVList) {
  foreach (var current in arrayElement) {
    ...
  }
}

answered Feb 25, 2011 at 20:35

JaredPar

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Comments

ChrisJ · Accepted Answer · 2011-02-25 20:35:52Z

1

You'd be much better off using foreach loops, rather than classical for loops.

With foreach your iteration is written:

foreach(string[] array in parsedData) {
    foreach(string element in array) {
        Console.WriteLine(element);
    }
}

With foreach you just say “iterate over all the elements”, you need not worry about how many elments there are.

answered Feb 25, 2011 at 20:35

ChrisJ

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Comments

Achilles · Accepted Answer · 2011-02-25 20:36:44Z

0

Each array will have a size because all arrays in .NET inherit from System.Array. Simply reference the array based on the list index and then you can simply iterate to MyArrayOfInterest.count-1

answered Feb 25, 2011 at 20:36

Achilles

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1 Comment

Joel Over a year ago

Right, my question is more the syntax of c# and iterating through a list of arrays

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