Regular Expressions 101

Pro

Group 1([ \t]*(?: )+[ \t]*| +[ \t]+|\t+ +[ \t]*)

1st Alternative[ \t]*(?: )+[ \t]*

Character Class[ \t]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\ta tab character (ASCII 9)

Non-Capturing Group(?: )+

+repeats the group contents below at least once:

 the literal text   (case sensitive)

Character Class[ \t]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\ta tab character (ASCII 9)

2nd Alternative +[ \t]+

+the literal (32₁₀ / 40₈ / 20₁₆) , repeated at least once

Character Class[ \t]+

+matches at least one character from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\ta tab character (ASCII 9)

3rd Alternative\t+ +[ \t]*

\t+a tab character (ASCII 9), repeated at least once

+the literal (32₁₀ / 40₈ / 20₁₆) , repeated at least once

Character Class[ \t]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\ta tab character (ASCII 9)

Global pattern flags

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

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Detailed match information will be displayed here automatically.

26 tokens

Regular Expression

([ \t]*(?:&nbsp;)+[ \t]*| +[ \t]+|\t+ +[ \t]*)

		
	 
 	
 
	
&nbsp;	
 &nbsp;
&nbsp;
  

The  fat		   &nbsp;&nbsp;  			cat 	   	  sat on  the  mat.  
Th							e	 			   			  	fat 	  cat  		sat			on 	 the	 mat. 	
The &nbsp;fat&nbsp;&nbsp;cat&nbsp; &nbsp;	 sat  on 	&nbsp;the  &nbsp;mat.&nbsp;
The&nbsp;fat&nbsp;cat	&nbsp;sat&nbsp; on&nbsp;the&nbsp;mat.&nbsp;

Substitution

		
	 
 	
 
	
&nbsp;	
 &nbsp;
&nbsp;
  

The  fat		   &nbsp;&nbsp;  			cat 	   	  sat on  the  mat.  
Th							e	 			   			  	fat 	  cat  		sat			on 	 the	 mat. 	
The &nbsp;fat&nbsp;&nbsp;cat&nbsp; &nbsp;	 sat  on 	&nbsp;the  &nbsp;mat.&nbsp;
The&nbsp;fat&nbsp;cat	&nbsp;sat&nbsp; on&nbsp;the&nbsp;mat.&nbsp;