Introduction | Binding Op | Reg Expressions | Examples | Substitution | Advanced
To try out what we learned in Regular Expressions it would be good to see a few pattern matches in practice to see how they go together.
Regular Expression | Meaning |
/a.c/ | the letter a followed by any character then c |
/a+c/ | one or more a's followed by c |
/a*c/ | zero or more a's followed by c, so even "c" matches. |
/a?c/ | zero or one a followed by c: "ac" or "c" |
/a.+c/ | a followed by one or more characters, then c |
/a.*c/ | a followed by zero or more characters, then c, so even "ac" matches. |
/a|bc/ | "a" or "bc" |
/(a|b)c/ | "ac" or "bc" |
/(a|b)+c/ | one or more a's or b's, followed by c: ac, bc, aac, abc, aaac, abbabababbac. |
/(a|A)\ssample\smatch/ | "A" or "a" followed by one whitespace character, then "sample", then one whitespace character, then "match". |
/\d\d\d-\d\d\d-\d\d\d\d/ | Any phone number like this: 250-123-1234 |
/\(\d\d\d\)\s\d\d\d\-\d\d\d\d/ | Any North American phone number like this: (250) 123-1234 |
/\(\d{3}\)\s\d{3}-\d{4}/ | As above, but using the count specifier |
/<title.*title>/ | An html title tag, with any title. The .* match would include the > and <\ characters |
/<title>.*<\/title>/ | An html title tag, with any title. The </title> tag needs a backslash quote in front of the slash, \/, to prevent the slash from being taken as the end of the pattern The .* match would include only the title text, not the > and </ as above |
/first.*second.*third/ | Any sequence of text with the word first before the word second before the word third. Any or no characters can lie in between the words |
/^\t+\S+\s*/ | Any line of text starting with one or more tabs, containing at least one nonwhitespace characer, followed by no or some whitespace |
/^b[aeiouy]+t/ | Any line of text starting with b followed by any combination of 1 or more vowels and then the letter t/ |
If you are comfortable with these examples, continue on to learn how to perform substitutions.