Regular expressions for finding text

.

Any character   acts as a wild card to match any single printing or non-printing character with the exception of the newline (\n)character.

For example, the regular expression c.t matches the strings cat, c t, cot, but not cost. In this example, the period (.) is a wild card for a single character. It appears between the letters 'c' and 't', so any single character between the characters 'c' and 't' will match the expression—even if it is a space.

+

Maximal—one or more   matches one or more occurrences of a character that precede the expression, matching as many characters as possible.

The regular expression .+ matches one or more occurrence of one character.

For example, the regular expression bo+. matches bob, book, and boot. In this example, we combine the period (.) with the plus sign (+) to make one syntax. The period (.) appears immediately after the plus sign (+) expression. The plus sign (+) matches one or more occurrences of the letter 'o'. The period (.) acts as a wild card for the last character of each word, which, in this example are 'b', 'k', and 't'.

#

Minimal—one or more   matches one or more occurrences of a character that precede the expression, matching as few characters as possible.

For example, the regular expression si.#er matches 'sicker' or 'silkier'. In this example, we combine the period (.) with the sharp sign (#) to make one syntax. The period (.) appears immediately before the sharp sign (#) expression. The sharp sign (#) matches one or more occurrences of any character between 'si' and 'er'. The period (.) acts as a wild card for the characters 'c' and 'k' in the word sicker, and 'l', 'k', and 'i' in the word silkier.

^

Beginning of line   anchors the match to the beginning of a line.

For example, the regular expression ^When in matches the any string that begins with "When in" and that also appears at the beginning of a line, such as "When in the course of human events" or "When in town, call me". Whereas, this regular expression does not match "What and when in the course of human events" if it appears at the beginning of a line.

^^

Beginning of file   anchors the match to the beginning of a file. Works only when searching for text in source code or in text files.

For example, to match the first HTML tag at the beginning of a file, use the following regular expression: ^^

|

Or   indicates a choice between two items, thereby matching the expression before or after the OR symbol (|).

For example, the regular expression (him|her) matches the following occurrences "it belongs to him" or "it belongs to her" but it does not match the line "it belongs to them."

{}

Tagged expression   tags the text matched by the enclosed expression. You can match another occurrence of the tagged text in a Find expression or insert the tagged text in a Replace expression using \N.

For example, suppose you are looking to find two duplicate, consecutive words. To search, use the following expression: {.#} \1

With the assumption that the consecutive words are separated by a single space, you'll want to add a space between the right curly brace (}) and the back slash ( \ ).

In this example, we combine the sharp sign (#) and the period (.) with the curly braces ({}) to make one syntax. In this expression, .# represents any consecutive characters. Since this portion of the expression is surrounded by curly braces ({}), the consecutive characters will be tagged and can be referred to as \1. This expression will find any consecutive characters followed by a space, followed by those exact same consecutive characters.

( )

Group expression    marks the beginning and end of a sub expression.

A sub expression is a regular expression that you enclose in parenthesis ( ), such as the expression that follows: (ha)+ In this example, we combine the plus sign (+) with the parenthesis ( ) group expression to make one syntax. The sub expression is (ha) because it is encapsulated within the parenthesis ( ). When you add the plus sign (+), the expression enables you to find repeating pairs of letters. The plus sign (+) represents one or more occurrences of 'ha'.

This expression matches the following occurrences 'haha' and 'hahaha'.

\n

Line break    matches a new line in Code view, or a <br> in Design view.

The syntax (\n), is a shorthand approach to enable you to match all line breaks.

[^]

Any one character not in the set    matches any character that is not in the set of characters that follows the caret (^).

For example, to match any character except those in the range, use the caret (^) as the first character after the opening bracket. The expression [^269A-Z] will match any characters except 2, 6, 9, and any upper case alphabetical characters.

:a

Alphanumeric character    matches the expression [a-zA-Z0-9].

You can use the following expression: [a-zA-Z0-9] to match one occurrence of a letter (upper case or lower case) or number. Also known as alphanumeric occurrences. You can use the shorthand expression :a for all instances of [a-zA-Z0-9].

:c

Alphabetic character    matches the expression [a-zA-Z]. When you use this expression, it enables you to match all upper or lower case letters.

You can use the shorthand expression :c for all instances of [a-zA-Z].

:h

Hexadecimal digit    matches the expression [0-9a-fA-F]+

Use a this expression when you want to match a hexadecimal combination of any upper or lower case letters between 'A' and 'F', and any numbers.

For example, suppose the pages in your site have multiple different background colors and you want to change the color of those pages to black, such as 000000. However, you do not know what the hexadecimal numbers are for the existing colors. Use the following regular expression to find all existing hexadecimal numbers:

\#:h

You could use [0-9a-fA-F] to search, but in this example we combine the back slash (\) and the sharp sign (#) with the hexadecimal digit (:h) syntax. \# matches a non-expression sharp sign (#) and :h matches any sequence of hexadecimal characters.

To replace the existing hexadecimal numbers, type the hexadecimal number of the background color that you want: 000000

:n

Rational number    matches the expression ([0-9]+\.[0-9]*)|([0-9]*\.[0-9]+)|([0-9]+)

If you want to match all whole numbers that contain a decimal point, you can use the shorthand expression :n to replace having to type the lengthy expression above.

:w

Alphabetic string    matches the expression [a-zA-Z]+

This syntax is a shorthand approach to enable you to match one or more alphabetical characters, either lower case or upper case.