tailieunhanh - Học JavaScript qua ví dụ part 83

Các trận đấu () Phương pháp Các trận đấu () phương pháp, như exec () phương thức, được sử dụng để tìm kiếm một mô hình của các ký tự trong một chuỗi và trả về một mảng mà mỗi phần tử của mảng chứa mỗi mẫu xuất hiện mà đã được tìm thấy. Nếu trận đấu không có được tìm thấy, trả về null. Với lá cờ g, phù hợp () tìm kiếm trên toàn cầu thông qua các chuỗi cho tất cả các chuỗi con phù hợp. . | String Methods Using Regular Expressions 727 EXPLANATION continued 8 leftContext is a class property that represents the leftmost substring pattern that precedes the last pattern that was matched here whatever string comes before Ilovel. 9 rightContext is a class property that represents the rightmost substring pattern that follows the last pattern that was matched here whatever string comes after Ilovel. Output is shown in Figure . Tested regular expression ove. The result is true. Starts searching again at position 6 in string 7 ove my new gloves The last matched characters were love The substring preceding the last match is I The substring following the last match is my new gloves Figure Regular expression properties. String Methods Using Regular Expressions In addition to the RegExp object s test and exec methods the String object provides four methods that also work with regular expressions as shown in Table . Table String Object Regular Expression Methods Method What It Does match regex Returns substring in regex or null. replace regex replacement Substitutes regex with replacement string. search regex Finds the starting position of regex in string. split regex Removes regex from string for each occurrence. The match Method The match method like the exec method is used to search for a pattern of characters in a string and returns an array where each element of the array contains each matched pattern that was found. If no match is found returns null. With the g flag match searches globally through the string for all matching substrings. From the Library of 728 Chapter 17 Regular Expressions and Pattern Matching FORMAT array regular_expression EXAMPLE matchList Too much too soon .match too ig EXAMPLE html head title The match Method title head body big font face arial helvetica script type text javascript 1 var matchArray new Array 2 var string I love the smell of clover. 3 var regex love g 4 .