Regex replace special character

Question

I need help in my regex.

I need to remove the special character found in the start of text

for example I have a text like this

.just a $#text this should not be incl#uded

The output should be like this

just a text this should not be incl#uded

I've been testing my regex here but i can't make it work

([\!-\/\;-\@]+)[\w\d]+

How do I limit the regex to check only the text that starts in special characters?

Thank you

Answer 1

Use \\B[!-/;-@]+\\s*\\b :

var result = Regex.Replace(s, @"\B[!-/;-@]+\s*\b", "");

See the regex demo

Details

• \\B - the position other than a word boundary (there must be start of string or a non-word char immediately to the left of the current position)
• [!-/;-@]+ - 1 or more ASCII punctuation
• \\s* - 0+ whitespace chars
• \\b - a word boundary, there must be a letter/digit/underscore immediately to the right of the current location.

If you plan to remove all punctuation and symbols, use

var result = Regex.Replace(s, @"\B[\p{P}\p{S}]+\s*\b", "");

See another regex demo .

Note that \\p{P} matches any punctuation symbols and \\p{S} matches any symbols.

Answer 2

Use lookahead:

(^[.$#]+|(?<= )[.$#]+)

The ^[.$#]+ is used to match the special characters at the start of a line.

The (?<= )[.$#]+) is used to matching the special characters at the start of a word which is in the sentence.

Add your special characters in the character group [] as you need.

Answer 3

Following are two possible options from your question details. Hope it will help you.

string input = ".just a $#text this should not be incl#uded";

//REMOVING ALL THE SPECIAL CHARACTERS FROM THE WHOLE STRING    
string output1 = Regex.Replace(input, @"[^0-9a-zA-Z\ ]+", "");

// REMOVE LEADING SPECIAL CHARACTERS FROM EACH WORD IN THE STRING. WILL KEEP OTHER SPECIAL CHARACTERS     
var split = input.Split();
string output2 = string.Join(" ",  split.Select(s=> Regex.Replace(s, @"^[^0-9a-zA-Z]+", "")).ToArray());

Answer 4

Negative lookahead is fine here :

(?![\.\$#].*)[\S]+

https://regex101.com/r/i0aacp/11/

[\\S] match any character

(?![\\.\\$#].*) negative lookahead means those characters [\\S]+ should not start with any of \\.\\$#