Regular Expression,缩写为regex、regexp、RE等; 分类 1、BRE 基本正则表达式,grep、sed、vi等软件支持,vim有扩展; 2、ERE 扩展正则表达式,egrep(grep -E)、sed -r等; 3、PCRE 几乎所有高级语言都是PCRE的方言或者变种;“grep -P” 使grep支持perl语言的正则表达式语法; 基本语法 元字符(metacharacter) .匹配...
\s Matches any whitespace character; equivalent to [ \t\n\r\f\v] in bytes patterns or string patterns with the ASCII flag. In string patterns without the ASCII flag, it will match the whole range of Unicode whitespace characters. \S Matches any non-whitespace character; equivalent to [^\...
字符与字符类(characters and character classes) 最简单的表达式就是字面意义上的字符,比如a或5,如果没有显式地指定量词, 就默认为“匹配一次”。比如,tune这一 regex包含了 4个表达式,每个都隐式地定量为匹配一次,因此,tune可以匹配的是t后跟随u,再之后是n,然后是...
\s -- (lowercase s) matches a single whitespace character -- space, newline, return, tab, form [ \n\r\t\f]. \S (upper case S) matches any non-whitespace character. \t, \n, \r -- tab, newline, return \d -- decimal digit [0-9] (some older regex utilities do not support...
整理用户输入的问题在编程过程中极为常见。通常情况下,将字符转换为小写或大写就够了,有时你可以使用正则表达式模块「Regex」完成这项工作。但是如果问题很复杂,可能有更好的方法来解决: user_input = "This\nstring has\tsome whitespaces...\r\n"
compile(r""" $ # end of line boundary \s{1,2} # 1-or-2 whitespace character, including the newline I # a capital I [tT][eE][mM] # one character from each of the three sets this allows for unknown case \s+ # 1-or-more whitespaces INCLUDING newline \d{1,2} # 1-or-2 ...
r';'), # Statement terminator ('ID', r'[A-Za-z]+'), # Identifiers ('OP', r'[+\-*/]'), # Arithmetic operators ('NEWLINE', r'\n'), # Line endings ('SKIP', r'[ \t]+'), # Skip over spaces and tabs ('MISMATCH', r'.'), # Any other character ] tok_regex = '|...
This example uses the following file,regexspaces.py, to show some ways you can use regex to remove whitespace characters: regexspaces.py importre s=' Hello World From DigitalOcean \t\n\r\tHi There 'print('Remove all spaces using regex:\n',re.sub(r"\s+","",s),sep='')# \s match...
re.VERBOSEXre.XAllows whitespaces and comments inside patterns. Makes the pattern more readableTry it » Special Sequences A special sequence is a\followed by one of the characters in the list below, and has a special meaning: CharacterDescriptionExampleTry it ...
对输入的的值进行清理处理，是常见的程序要求。比如要做大小写转化、要验证输入字符的注入，通常可以通过写正则用Regex来做专项任务。但是对于复杂的情况，可以用一些技巧，比如下面：user_input = "This\nstring has\tsome whitespaces...\r\n"character_map = { ord('\n') : ' ',ord('\t') : ' ',...