Regular Expressions 101

Explanation
Pro

Positive Lookbehind(?<=partn_key_yr_hr=)

partn_key_yr_hr=the literal text partn_key_yr_hr= (case sensitive)

Group 1(\d{10}|\d{8})

1st Alternative\d{10}

\d{10}a digit, repeated exactly 10 times

2nd Alternative\d{8}

\d{8}a digit, repeated exactly 8 times

Positive Lookahead(?=\/)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

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.

27 tokens

(?<=partn_key_yr_hr=)(\d{10}|\d{8})(?=\/)

New

csdasd/asdfadsf/partn_key_yr_hr=20220102/2343243dsfasdf=adsfadsf/

csdasd/asdfadsf/partn_key_yr_hr=20220102/2343243dsfasdf=adsfadsf/