Regular Expressions 101

Group 1(０|１|２|３|４|５|６|７|８|９)

1st Alternative０

０the literal ０ (65296₁₀ / 177420₈ / FF10₁₆)

2nd Alternative１

１the literal １ (65297₁₀ / 177421₈ / FF11₁₆)

3rd Alternative２

２the literal ２ (65298₁₀ / 177422₈ / FF12₁₆)

4th Alternative３

３the literal ３ (65299₁₀ / 177423₈ / FF13₁₆)

5th Alternative４

４the literal ４ (65300₁₀ / 177424₈ / FF14₁₆)

6th Alternative５

５the literal ５ (65301₁₀ / 177425₈ / FF15₁₆)

7th Alternative６

６the literal ６ (65302₁₀ / 177426₈ / FF16₁₆)

8th Alternative７

７the literal ７ (65303₁₀ / 177427₈ / FF17₁₆)

9th Alternative８

８the literal ８ (65304₁₀ / 177430₈ / FF18₁₆)

10th Alternative９

９the literal ９ (65305₁₀ / 177431₈ / FF19₁₆)

Positive Lookahead(?=.*:\1=(\w+))

.*any character, repeated any number of times

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\1the text saved by group 1

=the literal = (61₁₀ / 75₈ / 3D₁₆)

Group 2(\w+)

\w+any word character, repeated at least once

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

s modifier: single line. Allows a dot to match line terminators

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

Detailed match information will be displayed here automatically.

25 tokens

Regular Expression

(０|１|２|３|４|５|６|７|８|９)
(?=.*:\1=(\w+))

New

０ zero 
１ ichi 
２ ni 
３ san 
４ shi 
５ go
６ roku
７ shichi
８ hachi
９ kyuu
Dictionary:０=0:１=1:２=2:３=3:４=4:５=5:６=6:７=7:８=8:９=9

\2

０ zero 
１ ichi 
２ ni 
３ san 
４ shi 
５ go
６ roku
７ shichi
８ hachi
９ kyuu
Dictionary:０=0:１=1:２=2:３=3:４=4:５=5:６=6:７=7:８=8:９=9