Regular Expressions

Regular Expressions

Resources: See W3 Schools Tutorials for further information.

#### Common RegEx Characters

Character | Notes |
---|---|

? | 0 or 1 occurence of the preceding character |

+ | 1 or more occurences of the preceding character |

* | 0 or more occurences of the preceding character |

\ | Escape character |

. | Any character except newline |

\d | Single numeral |

\w | Single character from a to Z, 0-9, or underscore |

\s | White space character |

| | Either or |

() | within a group |

###### Example 1: Find all instances of a lowercase word that may be in the singular or plural e.g. garden or gardens

gardens?

###### Example 2: Find all instances of words that differ by a specified character e.g. shot or shoot

shoo?t

###### Example 3: Find all instances of a phrase with noun variations e.g. I like …

I like (dogs|cats|rabbits)

###### Example 4: Find all instances of a positive integer of one or more of a digit e.g. 9, 99, or 999

9+

###### Example 5: Find all “double 0” agent codes e.g. 007, 008, 009

00\d

###### Example 6: Recognize standard format dates e.g. 03/22/1990

\d\d/\d\d/\d\d\d\d

###### Example 7: Find all instances of positive integers of different lengths that begin with the same known digits followed by unknown digits e.g. 007 or 0014

00\d+

###### Example 8: Find all instances of positive integers of different lengths that begin with the same known digits followed by zero or more unknown digits e.g. 00, 007 or 0014

00\d*

###### Example 9: Find all instances of a decimal number e.g. 22**.**17

\d\d\.\d\d