Regular Expressions 101

Save & Share

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8

Function

  • Match
  • Substitution
  • List
  • Unit Tests
"
^([a-zA-ZáéíóúàèìòùÁÉÍÓÚÀÈÌÒÙ]+ )*+[a-zA-ZáéíóúàèìòùÁÉÍÓÚÀÈÌÒÙ]+$
"
gm
^ asserts position at start of a line
1st Capturing Group
([a-zA-ZáéíóúàèìòùÁÉÍÓÚÀÈÌÒÙ]+ )*+
*+ matches the previous token between zero and unlimited times, as many times as possible, without giving back (possessive)
A repeated capturing group will only capture the last iteration. Put a capturing group around the repeated group to capture all iterations or use a non-capturing group instead if you're not interested in the data
Match a single character present in the list below
[a-zA-ZáéíóúàèìòùÁÉÍÓÚÀÈÌÒÙ]
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
a-z matches a single character in the range between a (index 97) and z (index 122) (case sensitive)
A-Z matches a single character in the range between A (index 65) and Z (index 90) (case sensitive)
áéíóúàèìòùÁÉÍÓÚÀÈÌÒÙ
matches a single character in the list áéíóúàèìòùÁÉÍÓÚÀÈÌÒÙ (case sensitive)
matches the character with index 3210 (2016 or 408) literally (case sensitive)
Match a single character present in the list below
[a-zA-ZáéíóúàèìòùÁÉÍÓÚÀÈÌÒÙ]
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
a-z matches a single character in the range between a (index 97) and z (index 122) (case sensitive)
A-Z matches a single character in the range between A (index 65) and Z (index 90) (case sensitive)
áéíóúàèìòùÁÉÍÓÚÀÈÌÒÙ
matches a single character in the list áéíóúàèìòùÁÉÍÓÚÀÈÌÒÙ (case sensitive)
$ asserts position at the end of a line
Global pattern flags
g modifier: global. All matches (don't return after first match)
m modifier: multi line. Causes ^ and $ to match the begin/end of each line (not only begin/end of string)
Your regular expression does not match the subject string.

Regular Expression
No Match

"
"
gm

Test String