Replace Multiple Characters in string

You could also use a regex replacement.

s = System.Text.RegularExpressions.Regex.Replace(s, @"[)](\w+)[(]", "(1ドル)");

You cannot use Replace because it works its replacement operation on the whole string, not char by char.

A simple brute force solution could be this one

void Main()
{
 // A dictionary where every key points to its replacement char
 Dictionary<char, char> replacements = new Dictionary<char, char>()
 {
 {'(', ')'},
 {')', '('},
 };
 string source = ")Hi(";
 StringBuilder sb = new StringBuilder();
 foreach (char c in source)
 {
 char replacement = c;
 if(replacements.ContainsKey(c))
 replacement = replacements[c];
 sb.Append(replacement,1);
 }
 Console.WriteLine(sb.ToString());
}

You can transform this in an extension method adding to a static class

public static class StringExtensions
{
 public static string ProgressiveReplace(this string source, Dictionary<char, char> replacements)
 {
 StringBuilder sb = new StringBuilder();
 foreach (char c in source)
 {
 char replacement = c;
 if (replacements.ContainsKey(c))
 replacement = replacements[c];
 sb.Append(replacement, 1);
 }
 return sb.ToString();
 }
}

and call it from your code with

Dictionary<char, char> replacements = new Dictionary<char, char>() 
{{'(', ')'},{')', '('}};
s = s.ProgressiveReplace(replacements);

var s = ")Hi("; 
var sb = new StringBuilder();
foreach (var c in s)
 if (c == ')')
 sb.Append('(');
 else if (c == '(')
 sb.Append(')');
 else
 sb.Append(c);
s = sb.ToString();

Method 1) Use the following:

var requiredString = string.Join(string.Empty, str.Select(x=>{if (x == '(') x = ')'; else if (x == ')') x = '('; return x;}));

Method 2) Or you can Use following Extension Method:

public static class StringExtensions
{
 public static string ReplaceMultiple(this string source, Dictionary<char, char> replacements)
 {
 return string.Join(string.Empty , source.Select(x=>Replace(x,replacements)));
 }
 private static char Replace(char arg, Dictionary<char, char> replacements)
 {
 if(replacements.ContainsKey(arg))
 arg = replacements[arg];
 return arg;
 }
}

This method can be used as follows:

 var rep = new Dictionary<char, char> 
 { 
 { ')', '(' }, 
 { '(', ')' }, 
 // { '#', '*' }, 
 // { '*', '#' } 
 };
 var c = str.ReplaceMultiple(rep);

Regex.Replace lets you process each Match (needs using System.Text.RegularExpressions;) :

string result = Regex.Replace(")Hi(", @"\(|\)", m => m.Value == "(" ? ")" : "(");

Alternative can be replacing one of the characters with something else:

string result = ")Hi(".Replace('(', '0円').Replace(')', '(').Replace('0円', ')');

• c#