regex101: Python Match Workspace

(?im)applies the following effective flags to the remainder of the pattern: gim

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

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Non-Capturing Group(?:^[^\S\r\n]*\d+/\d+/\d+|.*\bprefix)

1st Alternative^[^\S\r\n]*\d+/\d+/\d+

^start of line

Negated Character Class[^\S\r\n]*

*matches any number of characters outside the set below:

\Sany character that is not Unicode whitespace

\ra carriage return (ASCII 13)

\na line-feed (newline) character (ASCII 10)

\d+a Unicode decimal digit, repeated at least once

/the literal / (47₁₀ / 57₈ / 2F₁₆)

\d+a Unicode decimal digit, repeated at least once

/the literal / (47₁₀ / 57₈ / 2F₁₆)

\d+a Unicode decimal digit, repeated at least once

2nd Alternative.*\bprefix

.*any Unicode character (except for line terminators), repeated any number of times

\ba Unicode word boundary

prefixthe literal text prefix (case insensitive)

.*any Unicode character (except for line terminators), repeated any number of times

Global pattern flags

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

Search reference

Regular Expression

(?im)(?:^[^\S\r\n]*\d+/\d+/\d+|.*\bprefix).*

New

                                                        Prefix : 0051601

    Data     Material                                       No. OS  Hist. Nr/Controle        Quant.       Vlr.Unit.            Vlr.Total 
 ----------------------------------------------------------------------------------------------------------------------------------------
 13/01/2008  00101050 Lampada farol H5 24V                          003   4863                2,000        9,870556              19,7411 
                                                                                        ====== Total dia 13/01/2008 ======
                                                                     Entradas :                                                         
                                                                     Saídas   :               2,000                              19,7411
                                                                     -------------------------------------------------------------------

Regular Expressions 101

Regular Expression

Substitution