c# regular Expression replace string-CodePudding

I have a string like below

this is a test string #1# random string #2# random string #30# random string #99#

the number is between #, the number can go from 1-99. the number is normally continuous from 1 to X, like #1#, #2#, #3#, #4#, but it could skip some numbers like #1#, #5#, #99#

I also have a dictionary like:

var dictionary = new Dictionary<int, string>()
{
    { 1, "value1" },
    { 2, "value2" },
    { 3, "value3" },
    { 4, "value4" },
};

I am looking for a regex to replace #X# with valueX, like #1# #2# #4# will be replaced as value1 value2 value4

what I have tried is

if(orgStr.contain("#1#")

  orgStr=orgStr.replace("#1#","value1")

if(orgStr.contain("#2#")

  orgStr=orgStr.replace("#2#","value2")

it works but obviously not optimal

Any idea how to do it with C# regex?

CodePudding user response：

It seems to me that the effort to create a Regex will produce more code than simply manipulating the string directly.

Try this:

var dictionary = new Dictionary<int, string>()
{
    { 1, "value1" },
    { 2, "value2" },
    { 3, "value3" },
    { 4, "value4" },
};

var text = "#1#  #2# #4#";

text =
    Enumerable
        .Range(1, 99)
        .Aggregate(text, (t, n) =>
            dictionary.ContainsKey(n)
            ? t.Replace($"#{n}#", dictionary[n])
            : t);

Console.WriteLine(text);

That produces:

value1  value2 value4

Here's the Regex version:

var regex = new Regex("#(\\d{1,2})#");

text = regex.Replace(text, m =>
    dictionary.ContainsKey(int.Parse(m.Groups[1].Value))
    ? dictionary[int.Parse(m.Groups[1].Value)]
    : m.Value);

Or:

text = regex.Replace(text, m =>
    dictionary
        .TryGetValue(int.Parse(m.Groups[1].Value), out string value) 
            ? value
            : m.Value);

Here's a simple loop approach:

for (int n = 1; n <= 99; n  )
{
    if (dictionary.ContainsKey(n))
    {
        text = text.Replace($"#{n}#", dictionary[n]);
    }
}

CodePudding user response：

You could use String.Replace() on each match found.

Like this:

var dictionary = new Dictionary<int, string>() {
    { 1, "value1" },
    { 2, "value2" },
    { 3, "value3" },
    { 4, "value4" },
};

string input = "some #1# string to compare to";

// Using RegEx
var rx = new Regex("\\#([0-9] )\\#", RegexOptions.Compiled);
MatchCollection matches = rx.Matches(input);

// Checking all matches
foreach (Match match in matches) {  
    // Getting the key
    int key = int.Parse(match.Groups[1].Value);

    input = input.Replace(match.Value, dictionary[key]);
}

This was written on my phone without prior testing so please do let me know if it works for you.