Regular expressions and regular languages

The use of regular expressions for many years, but has been stuck in only the use of the recent reading process, suddenly a new understanding of the regular:

1, the so-called regular, English for regular, did not want to understand, yesterday suddenly thought of its meaning is to explain that the expression is a rule, not a mess. With the rules, we can analyze and deal with all kinds of laws. There is no regular expression, we do not care, and no interest, of course, no rule is also said to be an example, not worth studying.

2, the regular expression is not a single specific content, but a series of specific content, but all of these specific content by the regular expression in the alphabet by the combination of characters. The set of all the specific content represented by a regular expression is the range that the regular expression can represent, that is, the regular language, which can be defined by regular expressions, or can be exhaustive.

Regular expressions and regular languages