MEPX
Chapter 8 of 10All chapters
  1. 1What a regex is
  2. 2Literals and classes
  3. 3Quantifiers
  4. 4Anchors and boundaries
  5. 5Groups and alternation
  6. 6Escaping
  7. 7Lookaround
  8. 8Flags
  9. 9When regex goes wrong
  10. 10Writing readable patterns

Chapter 8 of 10

Flags

Changing how the whole pattern behaves.

The common ones

Ignore case, multiline so anchors apply per line, dot-all so the dot also matches newlines, and global so every match is found rather than the first.

  • Global is a property of the search in some languages and of the pattern in others.
  • A stateful global regex object can surprise you by resuming from where it stopped.

Unicode

Turning on Unicode mode changes what counts as a word character and lets you match by script or property, which matters for any text beyond English.