C# String replace with dictionary

Question

I have a string on which I need to do some replacements. I have a Dictionary where I have search-replace pairs defined. I have created fol

Answer 1

Do this with Linq:

var newstr = dict.Aggregate(str, (current, value) => 
     current.Replace(value.Key, value.Value));

dict is your search-replace pairs defined Dictionary object.

str is your string which you need to do some replacements with.

Answer 2

Here you are:

public static class StringExm
{
    public static String ReplaceAll(this String str, KeyValuePair<String, String>[] map)
    {
        if (String.IsNullOrEmpty(str))
            return str;

        StringBuilder result = new StringBuilder(str.Length);
        StringBuilder word = new StringBuilder(str.Length);
        Int32[] indices = new Int32[map.Length];

        for (Int32 characterIndex = 0; characterIndex < str.Length; characterIndex++)
        {
            Char c = str[characterIndex];
            word.Append(c);

            for (var i = 0; i < map.Length; i++)
            {
                String old = map[i].Key;
                if (word.Length - 1 != indices[i])
                    continue;

                if (old.Length == word.Length && old[word.Length - 1] == c)
                {
                    indices[i] = -old.Length;
                    continue;
                }

                if (old.Length > word.Length && old[word.Length - 1] == c)
                {
                    indices[i]++;
                    continue;
                }

                indices[i] = 0;
            }

            Int32 length = 0, index = -1;
            Boolean exists = false;
            for (int i = 0; i < indices.Length; i++)
            {
                if (indices[i] > 0)
                {
                    exists = true;
                    break;
                }

                if (-indices[i] > length)
                {
                    length = -indices[i];
                    index = i;
                }
            }

            if (exists)
                continue;

            if (index >= 0)
            {
                String value = map[index].Value;
                word.Remove(0, length);
                result.Append(value);

                if (word.Length > 0)
                {
                    characterIndex -= word.Length;
                    word.Length = 0;
                }
            }

            result.Append(word);
            word.Length = 0;
            for (int i = 0; i < indices.Length; i++)
                indices[i] = 0;
        }

        if (word.Length > 0)
            result.Append(word);

        return result.ToString();
    }
}