regex101: Python Match Workspace

(?i)applies the following effective flags to the remainder of the pattern: gi

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

Negative Lookbehind(?<!\S)

\Sany character that is not Unicode whitespace

Group 1(\()?

?repeats the group contents below at most once:

\(the literal ( (40₁₀ / 50₈ / 28₁₆)

\ba Unicode word boundary

Non-Capturing Group(?:red|gold|silver|king)

1st Alternativered

redthe literal text red (case insensitive)

2nd Alternativegold

goldthe literal text gold (case insensitive)

3rd Alternativesilver

silverthe literal text silver (case insensitive)

4th Alternativeking

kingthe literal text king (case insensitive)

packthe literal text pack (case insensitive)

Condition(?(1)\))

Uses the first branch if group 1 matched

If the condition is true, match this branch:\)

\)the literal ) (41₁₀ / 51₈ / 29₁₆)

Non-Capturing Group(?: (?:70|8[34]|1[02]0)'?s)?

?repeats the group contents below at most once:

the literal (32₁₀ / 40₈ / 20₁₆)

Non-Capturing Group(?:70|8[34]|1[02]0)

1st Alternative70

70the literal text 70

2nd Alternative8[34]

8the literal 8 (56₁₀ / 70₈ / 38₁₆)

Character Class[34]

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

4the literal 4 (52₁₀ / 64₈ / 34₁₆)

3rd Alternative1[02]0

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[02]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

'?optionally matches the literal ' (39₁₀ / 47₈ / 27₁₆)

sthe literal s (115₁₀ / 163₈ / 73₁₆) (case insensitive)

Non-Capturing Group(?:\b(?:red|gold|silver|king) )?

?repeats the group contents below at most once:

\ba Unicode word boundary

Non-Capturing Group(?:red|gold|silver|king)

1st Alternativered

redthe literal text red (case insensitive)

2nd Alternativegold

goldthe literal text gold (case insensitive)

3rd Alternativesilver

silverthe literal text silver (case insensitive)

4th Alternativeking

the literal (32₁₀ / 40₈ / 20₁₆)

\ba Unicode word boundary

Non-Capturing Group(?:70|8[34]|1[02]0)

?optionally matches the literal (32₁₀ / 40₈ / 20₁₆)

Non-Capturing Group(?:'s)?

boxthe literal text box (case insensitive)

\ba Unicode word boundary

Global pattern flags

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

Search reference

Regular Expression

(?i)(?<!\S)(?:(\()?\b(?:red|gold|silver|king) pack(?(1)\))(?: (?:70|8[34]|1[02]0)'?s)?|(?:\b(?:red|gold|silver|king) )?\b(?:70|8[34]|1[02]0) ?(?:'s)?) box\b

Test String
New

Python does not support conditionals using lookaround, even though Python does support lookaround outside conditionals. Instead of a conditional like (?(?=regex)then|else), you can alternate two opposite lookarounds: (?=regex)then|(?!regex)else.

https://www.regular-expressions.info/lookaround.html
https://www.regular-expressions.info/conditional.html

LOOKAHEAD to see if EITHER pattern1 or pattern2 exists
pattern1 = ((\()?(red|gold|silver|king)( pack)?(\))?)
pattern2 = ((70|83|84|100|120)(s|'s)?)
IF one of the patterns exists in the string, THEN look for 
pattern1 box
pattern2 box
pattern1 pattern2 box
 
IS NOT cases - things that I do NOT want to match
box
 box
Marlboro Box - this is a perfect example of a NOT case - I do NOT want to match this string
OR maybe I do ... ARGH - NO I do not want to match BOX!!
moving box - example that I NEVER want to match ... ARGHHH
junk 's matchbox car
matchboxracer
boxer - we NEVER think about the NOT cases ... lol mitch and I fought about this for years. recently he meantioned the NEED for NOT

thing red (pack) gold box other thing

IS cases - aka - things that I WANT TO MATCH

Marlboro 100's Box
Marlboro Gold Pack 100's Box
Marlboro Special Blend (Gold Pack) 100's Box
Marlboro Silver Pack Box
Marlboro Special Blend (Red Pack) 100s Box
Pall Mall RED 100 BOX
Marlboro Special Blend (Gold Pack) Box

Regular Expression

Test StringNew

Test String
New