How to remove only symbols from string in dart

There are two issues:

• '\W' is not a valid escape sequence, to define a backslash in a regular string literal, you need to use \\, or use a raw string literal (r'...')
• \W regex pattern matches any char that is not a word char including whitespace, you need to use a negated character class with word and whitespace classes, [^\w\s].

Use

void main() {
  String s = "Hello, world! i am 'foo'";
  print(s.replaceAll(new RegExp(r'[^\w\s]+'),''));
}

Output: Hello world i am foo.

Fully Unicode-aware solution

Based on What's the correct regex range for javascript's regexes to match all the non word characters in any script? post, bearing in mind that \w in Unicode aware regex is equal to [\p{Alphabetic}\p{Mark}\p{Decimal_Number}\p{Connector_Punctuation}\p{Join_Control}], you can use the following in Dart:

void main() {
  String s = "Hęllo, wórld! i am 'foo'";
  String regex = r'[^\p{Alphabetic}\p{Mark}\p{Decimal_Number}\p{Connector_Punctuation}\p{Join_Control}\s]+';
  print(s.replaceAll(RegExp(regex, unicode: true),''));
}
// => Hęllo wórld i am foo

The docs for the RegExp class state that you should use raw strings (a string literal prefixed with an r, like r"Hello world") if you're constructing a regular expression that way. This is particularly necessary where you're using escapes.

In addition, your regex is going to catch spaces as well, so you'll need to modify that. You can use RegExp(r"[^\s\w]") instead - that matches any character that's not whitespace or a word character

I found this question looking for how to remove a symbol from a string. For others who come here wanting to do that:

final myString = 'abc=';
final withoutEquals = myString.replaceAll(RegExp('='), ''); // abc

First solution

s.replaceAll(RegExp(",|!|'"), "");    // The | operator works as OR

Second solution

s.replaceAll(",", "").replaceAll("!", "").replaceAll("'", "");

Removing characters "," from string:

String myString = "s, t, r";
myString = myString.replaceAll(",", ""); // myString is "s t r"