Regular Expressions 101

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An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
No Match

r"
"
g

Test String

Code Generator

Language

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "(//[^\\n]+)|(/\\*.*?\\*/)"; final String string = "#define MC2\n" + "#define MC1\n\n" + "# ifndef MCTEST\n" + "#define MCTEST\n" + " \n" + "#ifdef MC1 \n\n" + "#define data1 0x20\n" + "/*cmment start*/#define /*this is comment*/ data2 2.5f\n" + "#define date3 L\"this is a data\"\n" + "#define data4 true\n\n\n" + "#ifdef MC2\n\n" + "#define data5 'a'\n" + "#define data6 { {2.0, \"abc\"}, {1.5, \"def\"}, {5.6f, \"7.2\"}} // ¸¡µãÓë×Ö·û´®×é³ÉµÄ½á¹¹Ìå³õʼ»¯¾ÛºÏ£¬ ÔÙ½øÒ»²½¾ÛºÏ×é³ÉÁËÊý×é\n\n" + "#else //else MC2\n\n" + "# define data5 {5.0, 7.5, 3.8}\n" + "#define data6 'c'\n\n" + "#endif //end MC2\n\n" + "#ifdef MC3\n" + " //¼ÙifǶÌ×£¬ÓÃÓÚ²âÊÔ£¬ÔÚÓ¦¸Ã±»ºöÂÔµÄÇé¿öÏ£¬#endifµÄ¼æÈÝÇé¿ö\n" + "#endif //end MC3\n\n" + "#else//else MC1\n" + "\"//ccc\"\n" + "\"/*bbb*/\"\n" + "\"/**/\"\n" + "//\"//bbb\"\n" + "/*\"jjjjj\"*/\n" + "#define data1 1.0f /* this is float\n" + "may be changed\n" + "*/\n" + "#define data2 2\n" + "#define date3 false\n" + "#define data4 \"this is a data\"\n\n\n" + "#ifdef MC2\n\n" + "#define data5 'B'\n" + "#define data6 {1, 6, 3}\n" + "#define data7 0xa\n\n" + "#else//else MC2\n\n" + "#define data5 'D'\n" + "#define data6 {1, 6}\n\n" + "#endif //end MC2\n\n" + "#endif //MC1\n\n" + "#ifdef MC2\n" + "#undef MC2\n" + "#endif\n\n" + "/*ÔÚ¶àÐÐ×¢ÊͺóÃæ½ô¸úÒ»¸öµ¥ÐÐ×¢ÊÍ*///½ô¸úµÄµ¥ÐÐ×¢ÊÍ\n\n" + "#endif // !MC_TEST"; final Pattern pattern = Pattern.compile(regex); final Matcher matcher = pattern.matcher(string); while (matcher.find()) { System.out.println("Full match: " + matcher.group(0)); for (int i = 1; i <= matcher.groupCount(); i++) { System.out.println("Group " + i + ": " + matcher.group(i)); } } } }

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html