CODEWITHSUNDEEP
c#
user575219
user575219

Reputation: 2440

Parsing the integer part of string

I have a string which could be entered as {n}d {n}h {n}m {n}s where {n} is a integer denoting the number of days, hours, min, sec. How would I extract this {n} number from the string?

The user does not have to enter all 4 - d, h, m, s. He could only enter 4d which means 4 days or 5h 2s which means 5 hours and 2 sec.

Here's what I have. Definitely there should be a better way to do this. Also, does not cover all cases. 

int d; int m; int h; int sec;
string [] split = textBox3.Text.Split(new Char [] {' ', ','});
List<string> myCollection = new List<string>();

foreach (string s in split)
{
    d = Convert.ToInt32(s.Substring(0,s.Length-1));
    h = Convert.ToInt32(split[1].Substring(1));
    m = Convert.ToInt32(split[2].Substring(1));
    sec = Convert.ToInt32(split[3].Substring(1));
}
dt  =new TimeSpan(h,m,s);

Upvotes: 0

Views: 386

Answers (5)

Olivier Jacot-Descombes
Olivier Jacot-Descombes

Reputation: 112352

You can refine your approach slightly

int d = 0;
int m = 0;
int h = 0;
int s = 0;

// Because of the "params" keyword, "new char[]" can be dropped.
string [] parts = textBox3.Text.Split(' ', ',');

foreach (string part in parts)
{
    char type = part[part.Length - 1];
    int value = Convert.ToInt32(part.Substring(0, part.Length - 1));
    switch (type) {
        case 'd':
            d = value;
            break;
        case 'h':
            h = value;
            break;
        case 'm':
            m = value;
            break;
        case 's':
            s = value;
            break;
    }
}

Now you have exactly the non missing parts set. The missing parts are still 0. You can convert the values to a TimeSpan with

var ts = TimeSpan.FromSeconds(60 * (60 * (24 * d + h) + m) + s);

This covers all cases!

Upvotes: 0

Michael Liu
Michael Liu

Reputation: 55389

If the order of days, hours, minutes, and seconds is fixed, then you can use a regular expression:

string input = textBox3.Text.Trim();
Match match = Regex.Match(input,
    "^" +
    "((?<d>[0-9]+)d)? *" +
    "((?<h>[0-9]+)h)? *" +
    "((?<m>[0-9]+)m)? *" +
    "((?<s>[0-9]+)s)?" +
    "$",
    RegexOptions.ExplicitCapture);

if (match.Success)
{
    int d, h, m, s;
    Int32.TryParse(match.Groups["d"].Value, out d);
    Int32.TryParse(match.Groups["h"].Value, out h);
    Int32.TryParse(match.Groups["m"].Value, out m);
    Int32.TryParse(match.Groups["s"].Value, out s);
    // ...
}
else
{
    // Invalid input.
}

Upvotes: 3

ChrisK
ChrisK

Reputation: 1218

There are various options here. You could either try to use the TimeSpan.TryParse function, however this requires a different input format. Another approach would be to split the string on a whitespace and iterate over each part. While doing so you can check if the part contains d, h, s, etc. and extract the value into the desired variable. You could even use RegEx to parse the string. Here is a example based on iteration:

    static void Main(string[] args)
    {
        Console.WriteLine("Enter the desired Timespan");
        string s = Console.ReadLine();

        //ToDo: Make sure that s has the desired format

        //Get the TimeSpan, create a new list when the string does not contain a whitespace.
        TimeSpan span = s.Contains(' ') ? extractTimeSpan(new List<string>(s.Split(' '))) : extractTimeSpan(new List<string>{s});

        Console.WriteLine(span.ToString());

        Console.ReadLine();
    }

    static private TimeSpan extractTimeSpan(List<string> parts)
    {
        //We will add our extracted values to this timespan
        TimeSpan extracted = new TimeSpan();

        foreach (string s in parts)
        {
            if (s.Length > 0)
            {
                //Extract the last character of the string
                char last = s[s.Length - 1];

                //extract the value
                int value;
                Int32.TryParse(s.Substring(0, s.Length - 1), out value);

                switch (last)
                {
                    case 'd':
                        extracted = extracted.Add(new TimeSpan(value,0,0,0));
                        break;
                    case 'h':
                        extracted = extracted.Add(new TimeSpan(value, 0, 0));
                        break;
                    case 'm':
                        extracted = extracted.Add(new TimeSpan(0, value, 0));
                        break;
                    case 's':
                        extracted = extracted.Add(new TimeSpan(0, 0, value));
                        break;
                    default:
                        throw new Exception("Wrong input format");
                }
            }
            else
            {
                throw new Exception("Wrong input format");
            }
        }

        return extr

Upvotes: 0

Jonathan Wood
Jonathan Wood

Reputation: 67193

One approach might be to use sscanf(), which would do this quite easily. I've implemented a version of this function in C# in this article.

If you needed better handling of potential syntax errors, then you'll want to just implement your own parser. I would do that by just inspecting each character, one by one.

Upvotes: 0

Oded
Oded

Reputation: 499002

Write a custom parser - using a state machine to determine what exactly each part in the string is.

The idea is to iterate over each character in the string and change state according to what it is. So, you would have a Number state and Day, Month, Hour, Seconds states, Space and Start End states.

Upvotes: 0

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