.net 4.0中的字符串操作

Question

I have been out of touch with programming for a while. I have some strings I want to format. They look like this:

,SUM(CASE WHEN [Level] IN('4') AND Program = 1 THEN 1 ELSE 0 END) as CNT1
,SUM(CASE WHEN [Level] IN('3') AND Program = 1 THEN 1 ELSE 0 END) as CNT2
,SUM(CASE WHEN [Level] IN('2') AND Program = 1 THEN 1 ELSE 0 END) as CNT3
,SUM(CASE WHEN [Level] IN('1') AND Program = 1 THEN 1 ELSE 0 END) as CNT4
,SUM(CASE WHEN [Level] IN('0') AND Program = 1 THEN 1 ELSE 0 END) as CNT5

I want to take this and change it to

,CNT1 = SUM(CASE WHEN [Level] IN('4') AND Program = 1 THEN 1 ELSE 0 END) 
,CNT2 = SUM(CASE WHEN [Level] IN('3') AND Program = 1 THEN 1 ELSE 0 END) 
,CNT3 = SUM(CASE WHEN [Level] IN('2') AND Program = 1 THEN 1 ELSE 0 END) 
,CNT4 = SUM(CASE WHEN [Level] IN('1') AND Program = 1 THEN 1 ELSE 0 END) 
,CNT5 = SUM(CASE WHEN [Level] IN('0') AND Program = 1 THEN 1 ELSE 0 END) 

right now I have a multiline textbox that I paste the strings in. I want to click a button and have it formatted into a second textbox.

This is what I've tried so far. but I am not sure what string functions to use format it the way i want.

            List<String> Items = new List<string>();
            string frTxt;
            foreach (string lne in txtM.Lines)
            {
                frTxt = "";
                frTxt = lne;

            }  

where txtM is the multiline textbox. If I do Console.WriteLine(lne); in the loop, it loops through successfully.

Answer 1

Assuming the format is always

,<text_1> as <text_2>

This the following will transform it to:

,<text_2> = <text_1>

txtM.Lines = txtM.Lines.Select(l => Regex.Replace(l, ",(.+) as (.+?)$", ",$2 = $1")).ToArray();

Explanation of regex:

• The "," and " as " match those exact strings
• "(.+)" greedy-matches at least one character, and captures it as the first group
• "(.+?)" non-greedy-matches at least one character and captures it as the second group
• "$" matches the end of the line

As a result of combining the greedy and non-greedy matching, we force the " as ..." to be the last occurrence (so if the string happens to contain " as " somewhere in it, that won't matter). By adding the "$" we ensure that the second capture takes everything to the end of the line (otherwise as it's a non-greedy match it would match just the first character after " as ", which isn't what we want).

The replacement simply constructs the new string using the two groups captured by the regex, adding the "=". We also manually add back the "," at the beginning because our regex matches on it and so it will be replaced by the replacement string. (This can be overcome but would probably make the regex more complex).

Answer 2

well, if it's just the beginning and end there, you can do

myString.Replace(",", ",CNT1 = ").Replace(" as CNT1", "");

There are a lot of ways to do this with the built in string methods

Check out the String documentation

Here's a fully functional and tested code snipit:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] strArr = 
            {
            ",SUM(CASE WHEN [Level] IN('4') AND Program = 1 THEN 1 ELSE 0 END) as CNT1",
            ",SUM(CASE WHEN [Level] IN('3') AND Program = 1 THEN 1 ELSE 0 END) as CNT2",
            ",SUM(CASE WHEN [Level] IN('2') AND Program = 1 THEN 1 ELSE 0 END) as CNT3",
            ",SUM(CASE WHEN [Level] IN('1') AND Program = 1 THEN 1 ELSE 0 END) as CNT4",
            ",SUM(CASE WHEN [Level] IN('0') AND Program = 1 THEN 1 ELSE 0 END) as CNT5",
            };

            //intellisence didn't like assignment in the foreach loop
            for(int i=0; i<strArr.Length; i++)
            {
                string cnt = Regex.Match(strArr[i], @"CNT\d+$").Value;
                strArr[i] = strArr[i].Replace(",", String.Format(",{0} = ",cnt)).Replace(String.Format(" as {0}", cnt), "");
            }

            foreach(string str in strArr)
            {
                Console.WriteLine(str);
            }

        }
    }
}

Answer 3

Check out Regex.Replace with regular expressions matching and Regex language .

You want to use grouping constructs (...) to capture place where to insert substring and second one to capture substring to insert.

Answer 4

This is very specific. Is your input string always going to have that format? In that case, you can use something like this:

        string s = textBox1.Text;
        var result = s.Split(',').ToList();
        result.ForEach(x =>
        {
            int removeAfter = x.LastIndexOf(" as CNT");
            string cntNum = x.Substring(x.LastIndexOf("CNT"), x.Length - 1);
            x = string.Format(",{0} = {1}", cntNum, x.Substring(0, removeAfter));
        });

But I strongly suggest looking into using regular expressions to search and replace.

Answer 5

I am assuming your are using a richTextbox with multines please seeexample how you can do it

private void FormatLinesInTextBox()
{
    int cnt = 1;
    foreach (string line in richTextBox1.Lines)
    {
        string cntNumber = cntNumber = "CNT" + cnt;
        richTextBox1.Lines[cnt - 1] = "," + cntNumber + line.Replace(cntNumber, string.Empty);
        cnt++;
    }
}