List of Regular Expressions

a	matches any value containing the letter a	apple, and, canal
^	matches the beginning of a string	The expression ^A stands for the 'A' in "Anthony goes to Spain," but does not stand for it in "Susan goes to Africa"
$	matches the end of a string	The expression t$ stands for the 't' in "seat," but does not stand for it in "teacher"
.	matches any single character	For example, .n will correspond to 'an' and 'on', but not to 'navy'.
[...]	matches any of the characters in the sequence	The expression [abd] allows entering words containing the letters in brackets: doll, bath, apricot. The expression [1-9] allows entering any number from 1 to 9. The '-' character is treated as a literal character if it is the last or the first character within the brackets, or if it follows a backslash: [abc-], [-abc], or [a\-bc].
[^...]	matches any character except those in the sequence	If you use expression [^abc] your respondents will not be allowed to input anything that contains letters a, b or c.

{m,n}	matches preceding character at least m, but not more than n times	For example, the expression a{1,3} means that you can enter words containing from 1 to 3 letters 'a'
{m,}	matches preceding character m or more times	The expression a{2,} allows entering words containing 2 or more letters 'a'
{,n}	matches preceding character from 0 to n times	The expression a{,2} allows you to enter words containing from 0 to 2 letters 'a'
*	matches preceding character 0 or more times	The expression bo* allows you to input words containing only one letter 'b' and 0 or more letters 'o'
+	matches preceding character 1 or more times	The expression a+ allows entering words containing 1 or more letters 'a'
?	matches preceding character 0 or 1 times	Using the expression e? you can input words containing 0 or 1 letter 'e'

|	alternative	The expression green|red means that you can input either 'green' or 'red'
( )	grouping	The expression (ca)* means that * refers to all characters in brackets and you can input words containing 0 or more letters 'c' and 'a'

\	toggles off the interpretation of metacharacters and converts the following alphacharacters (w,d,s) in metacharacters.	For example, * is a special character that means 0 or more occurrences of the preceding character should be specified; for example, a* means match 0 or more a's. To match * literally, precede it with a backslash; for example, a\* matches 'a*'.
\w	matches any single character classified as a "word" character: a letter or a number	The expression \w allows entering a letter or a number
\d	matches any digit character, equivalent to [0-9]	The expression \d allows entering a number from 0 to 9.
\s	matches any white space character (space, tab, new line, form feed)	The expression \s\w* allows to input only one white space and after it 0 or more letters or numbers.
\W	matches any non-"word" character	The expression \W means that you can enter everything except letters and numbers.
\D	matches any non-digit character	The expression \D allows entering everything except numbers.
\S	matches any non-whitespace character	The expression \S allows to input everything except white spaces.

^[0-5]?[0-9]$ - this simple expression allows to enter any whole number from 00 to 59. 1-digit numbers from 0 to 9 are allowed as well.

• ^ - asserts position at the beginning of the string
• [0-5] - matches a single character in the range between '0' and '5'
• ? - matches the preceding element 0 or 1 times
• [0-9] - matches a single character in the range between '0' and '9'
• $ - asserts position at the end of the string

You can use regular expressions if you need to create a format that will allow users to enter only phone numbers of the following types:

(756)667-7832 or (756) 667 - 7832 ext. 234

In this case the formula will look like \(\d{3}\)\s?\d{3}\s?-\s?\d{4}\s?(\w+\.?\s?\d+)*

• \(\) stands for brackets, \ is used to interpret () as simple brackets;
• \d{3} refers to the sequence of three digits (numbers 0 to 9);
• \d{4} refers to the sequence of four digits (numbers 0 to 9);
• \s? means that there can be no spaces or only one space;
• \w+ means that there can be one or more letters;
• \d+ means that there can be one or more digits (numbers 0 to 9);
• \.? stands for the dot, \ is used to interpret . as a simple dot and it means that there can be no dots or only one dot;
• (\w+\.?\s?\d+)* means that the combination of letters and numbers can occur many times or never at all.

Additional examples of complex expressions

^\d+$	Number	Any whole positive number + 0
(0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])[- /.](19|20)\d\d	Date	Matches a date in mm/dd/yyyy format from between 1900-01-01 and 2099-12-31. '-', '/', '.' can be used as separators.
^([a-z0-9]+(-[a-z0-9]+)*\.)+[a-z]{2,}$	Domain name	Example: www.keysurvey.com

'Phone' format

Popular formats