用正则表达式分割字符串

Question

I have a list of strings that look like this:

List<string> list = new List<string>;
list.add("AAPL7131221P00590000");
list.add("AAPL7131206C00595000");
list.add("AAPL7131213P00600000");

I would like to remove the date that is between AAPL7 and the next letter which is either C or P , and then add it to a new list. How do I use regex to get: 131221 , 131206 , or 131212 so I can populate a new list?

Answer 1

Consider the following code snippet...

string startPattern = "AAPL7"; // GOOGL, GOOG, etc
List<string> newlist = list
    .Select(n => Regex.Match(n, string.Format(@"(?<=^{0})\d+", startPattern)).Value)
    .ToList();

Answer 2

You don't need regex for this one, you can just use Substring , assuming that all your inputs will be the same number of characters.

var startingString = "AAPL7"; // holds whatever the starting string is
var input = "AAPL7131221P00590000";

var outputDate = input.Substring(startingString.Length, 6);

So if you wanted to make this a one-liner for making a collection:

List<string> allDates = yourInputValues
    .Select(x => x.Substring(startingString.Length, 6))
    .ToList();

Answer 3

        //Regex regex = new Regex("(\\w{5})(\\d*)(\\w*)");
        Regex regex = new Regex("(\\w*)(\\d{6})([PC])(\\d*)");
        List<string> list = new List<string>();
        list.Add("AAPL7131221P00590000");
        list.Add("AAPL7131206C00595000");
        list.Add("AAPL7131213P00600000");
        List<string> extracted = new List<string>();
        foreach (string item in list)
        {
            extracted.Add(regex.Split(item)[2]);
        }

Is this what you want?

Answer 4

I just add something that may help in case you have the different date length (ie 14131 for 31st, January 2014)

string startpart = "AAPL7"; // or whatever
string mainstring = "AAPL714231P00590000"; // or any other input

mainstring = mainstring.Substring(startpart.Length); //this will through away startpart

int index;
if (mainstring.IndexOf("P") >= 0) index = mainstring.IndexOf("P"); //if there is no "P" it gives -1
else index = mainstring.IndexOf("C");

string date = mainstring.Substring(0,index);

i guess it is a safe approach to handle wider cases