"Mastering Regular Expressions"--opening notes

Body

At the beginning of a more careful study of regular expressions, is still relatively exciting, because the work of the use of a lot of things. You can use regular expressions instead of a lot of hand-made things in the later sections. The combination of Python believes that there can be a lot of harvest today is the beginning of notes so the record is relatively small, but there is an important idea is to lay down, that is, a regular expression as a single character to read, rather than a word, from the regular expression inside the concept of forgetting the word. In the book example ^cat$ this regular expression should be so understood, match line start position ^, then match C, then match A, then match T, and then match the position of the end of the line $. There is, of course, more understanding here and there are some introductions later. Note that the following link online matches the regular expression using the bounding character may be a bit problematic and can only be identified as a row. So use caution, complete learning or with Perl or Python or shell bar, other languages are OK, with the ideas in the text, not through the language to achieve, belong to the schools, the specific situation is a little different.

工欲善其事, its prerequisite. Regular expression Online detection: Point I summed up the thought lay: There are no words in the regular expression:) Keep this fresh.