Regular Expressions 101

^start of line

Positive Lookahead(?=.{6}$)

.{6}any character (except for line terminators), repeated exactly 6 times

$end of line

*the literal (32₁₀ / 40₈ / 20₁₆) , repeated any number of times

\d*a digit, repeated any number of times

*the literal (32₁₀ / 40₈ / 20₁₆) , repeated any number of times

$end of line

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.

25 tokens

Regular Expression

^(?=.{6}$) *\d* *$

New

Example 1:

123456
Example 2:
12345 
Example 3:
 23456
Example 4:
     5
Example 5:
1     
Example 6:
      
Example 7:
  2   
Example 3:
 2345 
Should not match the following:

Example 1:

12 456
Example 2:
1234 6
Example 3:
 1   6
Example 4:
1    6