Regular Expressions 101

Explanation

Pro

1st Alternative(?:,|^)[ ]*1004[ ]*(?=,)

Non-Capturing Group(?:,|^)

1st Alternative,

,the literal , (44₁₀ / 54₈ / 2C₁₆)

2nd Alternative^

^start of line

Character Class[ ]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

1004the literal text 1004

Character Class[ ]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

Positive Lookahead(?=,)

,the literal , (44₁₀ / 54₈ / 2C₁₆)

2nd Alternative(?<=,)[ ]*1004[ ]*(?:,|$)

Positive Lookbehind(?<=,)

,the literal , (44₁₀ / 54₈ / 2C₁₆)

Character Class[ ]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

1004the literal text 1004

Character Class[ ]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

Non-Capturing Group(?:,|$)

1st Alternative,

,the literal , (44₁₀ / 54₈ / 2C₁₆)

2nd Alternative$

$end of line

3rd Alternative^[ ]*1004[ ]*$

^start of line

Character Class[ ]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

1004the literal text 1004

Character Class[ ]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

$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

Match Information

Detailed match information will be displayed here automatically.

Quick Reference

25 tokens

Regular Expression

(?:,|^)[ ]*1004[ ]*(?=,)|(?<=,)[ ]*1004[ ]*(?:,|$)|^[ ]*1004[ ]*$

New

 1004, 1001 , 11004, 1002, 1003, 1004 ,  1005,ABC100,10041,ABC102, 1004

Extraction

 1004, 1001 , 11004, 1002, 1003, 1004 ,  1005,ABC100,10041,ABC102, 1004