Regular Expressions 101

Explanation

Pro

Non-Capturing Group(?:\s+\$\s*(?P<in_line>[^$]+?)\s*\$\s+|^\s*\${2}\s*(?P<bloc>(?:[^$]{2})*?)\s*\${2})

1st Alternative\s+\$\s*(?P<in_line>[^$]+?)\s*\$\s+

\s+a Unicode whitespace character, repeated at least once

\$the literal $ (36₁₀ / 44₈ / 24₁₆)

\s*a Unicode whitespace character, repeated any number of times

Group in_line(?P<in_line>[^$]+?)

Negated Character Class[^$]+?

+?matches at least one character outside the set below:

$the literal $ (36₁₀ / 44₈ / 24₁₆)

\s*a Unicode whitespace character, repeated any number of times

\$the literal $ (36₁₀ / 44₈ / 24₁₆)

\s+a Unicode whitespace character, repeated at least once

2nd Alternative^\s*\${2}\s*(?P<bloc>(?:[^$]{2})*?)\s*\${2}

^start of line

\s*a Unicode whitespace character, repeated any number of times

\${2}the literal $ (36₁₀ / 44₈ / 24₁₆) , repeated exactly 2 times

\s*a Unicode whitespace character, repeated any number of times

Group bloc(?P<bloc>(?:[^$]{2})*?)

Non-Capturing Group(?:[^$]{2})*?

*?repeats the group contents below any number of times:

Negated Character Class[^$]{2}

{2}matches exactly 2 characters outside the set below:

$the literal $ (36₁₀ / 44₈ / 24₁₆)

\s*a Unicode whitespace character, repeated any number of times

\${2}the literal $ (36₁₀ / 44₈ / 24₁₆) , repeated exactly 2 times

Global pattern flags

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

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

Match Information

Detailed match information will be displayed here automatically.

Quick Reference

25 tokens

Regular Expression

(?:\s+\$\s*(?P<in_line>[^$]+?)\s*\$\s+|^\s*\${2}\s*(?P<bloc>(?:[^$]{2})*?)\s*\${2})

New

Lorem ipsum dolor sit ame $ a = \{ b, c \} $ Lorem 100 \$ ipsum
$$ \left \{ 
    \begin{array}{cl}y_1 =&3 x_1 - x_2 + x_3\\y_2 =&2 x_2\\y_3 =&x_1 - x_2 + 3 x_3\end{array} 
    \right.
    \Leftrightarrow  \left \{ 
    \begin{array}{cl}8 x_1 =&3 y_1 + y_2 -y_3\\8 x_2 =&4 y_2\\8 x_3 =&-y_1 + y_2 + 3 y_3\end{array} 
    \right.
    $$ 
Lorem ipsum dolor
  $$ \left \{ 
    \begin{array}{cl}y_1 =&3 x_1 - x_2 + x_3\\y_2 =&2 x_2\\y_3 =&x_1 - x_2 + 3 x_3\end{array} 
    \right.
    \Leftrightarrow  \left \{ 
    \begin{array}{cl}8 x_1 =&3 y_1 + y_2 -y_3\\8 x_2 =&4 y_2\\8 x_3 =&-y_1 + y_2 + 3 y_3\end{array} 
    \right.
    $$ 
Lorem ipsum dolor $$$ Lorem ipsum dolor $$$. foo sit ame $ a = \{ b, c \} $