 Okay, now what happen say if we want to match a special character from within a character class for example the character sign, dollar sign or the period dot or the opening square bracket or backslash which is also called a meta characters. So the simplest way to match the special character is to escape them by simply adding the backslash before that character like this. Alright, now let us move ahead. Character ranges generally follow the character order of the local. Here what I mean to say is let's look at this ASCII character table. As you can see if you use capital A to capital P as the range all is fine and the correct group of character is selected. However, if I change the range to go from capital A to lowercase D the characters between the capital Z and the lowercase A are also selected. Obviously, this is just a simple example, but be careful when you define your character ranges in your regular expression using this character class. Another thing to be very of is the order in which you give the characters to define a range. Again, say for example, if I define my range as 0 to 9 then then no problem as it is a valid range. However, if I define the ranges as 9 to 0 the behavior is not completely defined. That means your regex is considered either invalid or it may happen that your regex engine might throw an error. So be careful when you define the character order within the regex. Let's move ahead. In some of the card games the Joker is a wild card and used to represent any other playing card. But with certain restrictions, same way in regular expression there is a concept of wild card which is represented by the dot meta character. The dot will generally match anything like alphabetic or numeric character or white space, punctuations and any other symbols except the new line character. When using a dot within a character class it loses its special meaning and matches just a literal dot. So here this a dot c matches only either a or dot or c. But if I remove this character class then it matches a b c or a d c etc. So using a dot within a character class as a wild card would be a kind of senseless anyways as it already matches everything. Alright so this is the end of part 1 of module 2. In the next part we will learn about the quantifiers, meta character alternation, subpattern and grouping. So stay tuned and see you in the next part.