Regular Expression learning instance and regular expression instance

Regular Expression learning instance and regular expression instance

Example 1:

Regular :(? <= (Href | src | filepath) =) \ S +? (\. Jpg | \. JPG)

Resolution: The expression is divided into three sections.

Section 1:

(? <= (Href | src | filepath) =) the starting position of the query indicates that the match starts from the starting position of href =, src =, and filepath =.

Use the regular expression (? <=Pattern). If no, the match starts from this character.

Section 2:

\ S +? The configuration character in the middle. Note? Indicates the minimum match, that is, the first match in the future.

Section 3:

(\. Jpg | \. JPG.

 

This expression can be used to obtain the address after href, src, or filepath.

For example,

Match result as http://avatar.csdn.net/8/3/2/1_xanxus46.jpg

 

Example 2

Regular: (.) \ 1 (.) \ 2

Expressions Used

\ Num matches num, where num is a positive integer. References to the obtained matching. For example, "(.) \ 1" matches two consecutive identical characters. Resolution: match two (identical) repeated characters. For example, the htttpp matching result ttpp (different) The httttpp matching result is tttt (Same)