CODEWITHSUNDEEP
c#
Maher Khalil
Maher Khalil

Reputation: 539

Replace Multiple Characters in string

Hi all a have a program working but return string like ")Hi(" it should be "(Hi)" so i need to replace '(' with ')' and replace ')' with '(' it sounds easy 

s.Replace('(',')').Replace(')','(')

the trick is that after the first replace the string change from ")Hi(" to "(Hi(" after the second the replace will change both characters back the final will become ")Hi)" Help Please

Upvotes: 2

Views: 5898

Answers (5)

LukStorms
LukStorms

Reputation: 29647

You could also use a regex replacement. 

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

Upvotes: 2

Slai
Slai

Reputation: 22876

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').Replace(')', '(').Replace('\0', ')');

Upvotes: 0

Deepak Tiwari
Deepak Tiwari

Reputation: 186

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);

Upvotes: 0

Alexander Petrov
Alexander Petrov

Reputation: 14231

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();

Upvotes: 0

Steve
Steve

Reputation: 216243

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);

Upvotes: 0

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