How to convert a char array to a string array?

Question

Given:

A string dayCodes (i.e. "MWF" or "MRFU") that I need to split and create a collection of strings so I can have a list of day of the week strings (i.e. "Monday", "Wednesday", "Friday" or "Monday", "Thursday", "Friday", "Sunday").

// this causes a run-time exception because you can't cast Char to String
var daysArray = days.ToCharArray().Cast<string>().ToArray();

// for each dayCode, overwrite the code with the day string.
for (var i = 0; i < daysArray.Length; i++)
{
    switch (daysArray[i])
    {
        case "M":
            daysArray[i] = "Monday";
            break;

        case "T":
            daysArray[i] = "Tuesday";
            break;

        case "W":
            daysArray[i] = "Wednesday";
            break;

        case "R":
            daysArray[i] = "Thursday";
            break;

        case "F":
            daysArray[i] = "Friday";
            break;

        case "S":
            daysArray[i] = "Saturday";
            break;

        case "U":
            daysArray[i] = "Sunday";
            break;
    }
 }

 daysArray[daysArray.Length - 1] = "and " + daysArray[daysArray.Length - 1];

 return string.Join(", ", daysArray);

Problem:

The problem is that you can't cast Char to String which I guess makes sense because one is not inherited from the other. Still you'd think that the compiler would cast the Char as a one character long String.

Is there a quick way (like using Cast<string>()) to do this so I don't have to create a List<string> from scratch?

BrokenGlass · Accepted Answer · 2011-10-29 00:54:48Z

28

Just using char.ToString() would work:

var daysArray = days.ToCharArray().Select( c => c.ToString()).ToArray();

Alternatively, and a better solution in my mind why don't you use the string directly with a dictionary for the mapping:

var daysArray = days.Select( c => dayMapping[c]).ToArray();

with dayMapping just a Dictionary<char, string> that maps to the full day name:

Dictionary<char, string> dayMapping = new Dictionary<char,string>()
{
    {  'M', "Monday" },
    {  'T', "Tuesday" }
    //and so on
}

edited Oct 29, 2011 at 0:54

answered Oct 29, 2011 at 0:49

BrokenGlass

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2 Comments

Andrew H Over a year ago

It'd be worth considering using the System.DayOfWeek enum in place of a magic string here, too.

aarona Over a year ago

@uglybugger I agree, except that the point of the method I'm making is to concatenate strings so it just be more code (i.e. having to call .ToString() on everything.

Matthew Flaschen · Accepted Answer · 2011-10-29 01:21:50Z

2

char[] daysCodeArray = days.ToCharArray();
string[] daysArray = daysCodeArray.Select(el =>
{
    switch (el)
    {
        case 'M':
            return "Monday";

        case 'T':
            return "Tuesday";

        case 'W':
            return "Wednesday";

        case 'R':
            return "Thursday";

        case 'F':
            return "Friday";

        case 'S':
            return "Saturday";

        case 'U':
            return "Sunday";
     }
     throw new ArgumentException("Invalid day code");
}).ToArray();

You can change the lambda into a separate method if you want.

edited Oct 29, 2011 at 1:21

answered Oct 29, 2011 at 0:53

Matthew Flaschen

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Comments

Kakashi · Accepted Answer · 2011-10-29 00:59:19Z

You can do this:

            var dayCode = "MWF";
            var daysArray = new List<string>();
            var list = new Dictionary<string, string>{
                {"M", "Monday"},
                {"T", "Tuesday"},
                {"W", "Wednesday"},
                {"R", "Thursday"},
                {"F", "Friday"},
                {"S", "Saturday"},
                {"U", "Sunday"}
            };

            for(int i = 0,max = dayCode.Length; i < max; i++)
            {
                var tmp = dayCode[i].ToString();
                if(list.ContainsKey(tmp))
                {
                    daysArray.Add(list[tmp]);
                }
            }
            Console.WriteLine(string.Join(",", daysArray));

Output:

enter image description here

Rakesh Sharma · Accepted Answer · 2016-04-15 16:55:22Z

1

To answer the question in the title for anyone finding this in a search...(not the problem as described...thats one of earlier posts.)

var t = "ABC";
var s = t.ToCharArray().Select(c => c.ToString()).ToArray();

answered Apr 15, 2016 at 16:55

Rakesh Sharma

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