php 正则表达式的模式修正符（Schema modifier for PHP regular expressions）.docVIP

php 正则表达式的模式修正符（Schema modifier for PHP regular expressions） The regular expression pattern modifier I: the pattern string will also match the letters. M: string as multiple lines. S: string as a single newline, as ordinary characters. X: blank in the pattern of neglect. A: from the beginning of the target compulsory only at the beginning of the string matching. D: at the end of $character mode only matching the target string. U: Recently, the string. PHP and regular expression patterns in modifier The following is a list of the current correction in PCRE may use the symbol. In parentheses is these modifiers inside PCRE. I (PCRE_CASELESS) If you set this modifier, the characters in the pattern will also match the letters. M (PCRE_MULTILINE) By default, PCRE will be the target string as a single character consisting of (even including a newline is). Starting line element character (^) only matching string starting, end of line character yuan ($) only matching the end of a string, or the last character is at the front of a newline (unless the set D modifier). This is the same as Perl. When setting the modifier, start and end of line, in addition to the entire string at the beginning and the end, respectively, after the newline and before. The Perl and /m modifiers are equivalent. If the target string no \n character or pattern or not ^ $, setting the modifier has no effect. S (PCRE_DOTALL) If you set this modifier, dot element character mode in (.), all of the characters, including the newline. Without this set of words, not including the newline. The Perl and /s modifiers are equivalent. Out of character classes such as [^a] always match a newline, regardless of whether the modifier set. X (PCRE_EXTENDED) If you set this modifier pattern in the blank character in addition to being outside the escape or in a character class is completely ignored, in unescaped character class outside the # and all of the characters, the next newline including two, are ignored. The Perl