set of alphabets E = {0,....,9,+,#,(, ) } code example
Example: javascript regex match character from a set of characters
// Regex - Any character from a set of characters
console.log(/[0123456789]/.test("in 1992")); // true
console.log(/[0-9]/.test("in 1992")); // true
console.log(/[abc]/.test("def")); // false
console.log(/[abc]/.test("cdef")); // true