regex101: Python Substitution Workspace

Pro

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

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(?: ( [ \t] )+ # (1) \b (?: \d+ | [a-z] ) \b [ \t]* [ \t]* | ^ \b (?: \d+ | [a-z] ) \b [ \t]* [ \t]* ( ) # (2) )

1st Alternative ( [ \t] )+ # (1) \b (?: \d+ | [a-z] ) \b [ \t]* [ \t]*

Group 1( [ \t] )+

+repeats the group contents below at least once:

Character Class[ \t]

the literal (32₁₀ / 40₈ / 20₁₆)

\ta tab character (ASCII 9)

Comment: (1)

\ba Unicode word boundary

Non-Capturing Group(?: \d+ | [a-z] )

1st Alternative \d+

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

2nd Alternative [a-z]

Character Class[a-z]

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

\ba Unicode word boundary

Character Class[ \t]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\ta tab character (ASCII 9)

Character Class[ \t]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\ta tab character (ASCII 9)

2nd Alternative ^ \b (?: \d+ | [a-z] ) \b [ \t]* [ \t]* ( ) # (2)

^start of line

\ba Unicode word boundary

Non-Capturing Group(?: \d+ | [a-z] )

1st Alternative \d+

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

2nd Alternative [a-z]

Character Class[a-z]

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

\ba Unicode word boundary

Character Class[ \t]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\ta tab character (ASCII 9)

Character Class[ \t]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\ta tab character (ASCII 9)

Group 2( ) — does not consume characters

Comment: (2)

Global pattern flags

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

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

25 tokens

Regular Expression

(?im)
(?:
   ( [ \t] )+           # (1)
   \b 
   (?: \d+ | [a-z] )
   \b [ \t]* [ \t]* 
 | ^ \b 
   (?: \d+ | [a-z] )
   \b [ \t]* [ \t]* 
   ( )                  # (2)
)

New

There is    a way 400 to trim8 wsp. t  
p   From both sides.

Substitution

\1\2

There is    a way 400 to trim8 wsp. t  
p   From both sides.