Regular Expressions 101

Pro

1st Alternative(?!_|^w)[^a-zA-Z]*

Negative Lookahead(?!_|^w)

1st Alternative_

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

2nd Alternative^w

^start of line

wthe literal w (119₁₀ / 167₈ / 77₁₆) (case sensitive)

Negated Character Class[^a-zA-Z]*

*matches any number of characters outside the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

2nd Alternative^_+

^start of line

_+the literal _ (95₁₀ / 137₈ / 5F₁₆) , repeated at least once

3rd Alternative[^a-zA-Z]*(?=_|$)

Negated Character Class[^a-zA-Z]*

*matches any number of characters outside the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

Positive Lookahead(?=_|$)

1st Alternative_

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

2nd Alternative$

$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

(?!_|^w)[^a-zA-Z]*|^_+|[^a-zA-Z]*(?=_|$)

New

*OIL~
OIL_GAS_
*OIL_GAS$
OIL_GAS
_OIL__GAS_