{"id":285,"date":"2011-07-29T14:23:16","date_gmt":"2011-07-29T14:23:16","guid":{"rendered":"http:\/\/www.extradrm.com\/?p=285"},"modified":"2011-07-29T14:23:16","modified_gmt":"2011-07-29T14:23:16","slug":"regular-expressions-in-marcedit","status":"publish","type":"post","link":"https:\/\/www.extradrm.com\/?p=285","title":{"rendered":"Regular Expressions in MarcEdit"},"content":{"rendered":"

Using Regular Expressions in MarcEditor Replacement Functions:<\/strong><\/p>\n

Regular Expressions can now be utilized in the Replace and Edit Subfield functions in the MarcEditor.<\/p>\n

This allows users to create complex search and replacement functions. In general, MarcEdit’s Regular Expression implemention is fairly straightforward. First, MarcEdit uses a replace\/with structure, meaning that the regular expression must be broken into a pattern and a replacement argument. Second, MarcEdit’s implementation is slightly different from the traditional unix greg implementation. For example, if there was a field containing the following data:<\/p>\n

aaabbb<\/p><\/blockquote>\n

And the user wanted the final output to look like:<\/p>\n

aaabxxbb<\/p><\/blockquote>\n

In Unix, one might use the following regular expression:<\/p>\n

\/ab\/\u0000xx\/<\/p><\/blockquote>\n

Using the Replace Function, this same expression would be written like :<\/p>\n

In the Find Text Textbox: ab<\/strong><\/p>\n

In the Replace With Textbox: \u00001xx<\/strong><\/p>\n

Check the Use Regular Expression<\/strong> option<\/p>\n

In MarcEdit, regular expressions should use the format defined below:<\/p>\n

Regular Expression Syntax in MarcEdit:<\/span><\/strong><\/span><\/p>\n

char definition:<\/span><\/strong><\/p>\n

. (period)<\/strong> : Matches any character, except the end-of-line.<\/p>\n

^ (caret)<\/strong> : Matches the actual beginning-of-line position or the preceding line-delimiter character pair (also see [^] below for usage within a character class definition).<\/p>\n

$ (dollar)<\/strong> : Matches the end-of-line position.<\/p>\n

| (stile)<\/strong> : Specifies alternation (the OR operator),<\/p>\n

so that an expression on either side can match. Precedence is from left-to-right<\/span>, as encountered in the expression.<\/p>\n

? (question mark)<\/strong> : Specifies that zero or one match of the preceding sub-pattern is allowed. Cannot be used with a Tag.<\/p>\n

+ (plus)<\/strong> : Specifies that one or more matches of the preceding sub-pattern are allowed. Cannot be used with a Tag.<\/p>\n

* (asterisk)<\/strong> : Specifies that zero or more matches of the preceding sub-pattern are allowed. Cannot be used with a Tag.<\/p>\n

 <\/p>\n

Character Classes<\/span><\/strong><\/p>\n

[ ] (square brackets)<\/strong> Identifies a user-defined class of characters, any of which will match: [abc] will match a, b, or c.<\/span> Only three special metacharacters are recognized within a class definition, the caret (^)<\/strong> for complemented characters, the hyphen (-)<\/strong> for a range of characters, or one of the following backslash escape sequences :<\/p>\n

\\ – ] e f n q r t v x##<\/strong><\/p>\n

Any other use of a backslash within a class definition yields an undefined operation that should be avoided.<\/p>\n

 <\/p>\n

[-] (hyphen)<\/strong> The hyphen identifies a range of characters to match.
\nFor example, [a-f] will match a, b, c, d, e, or f.<\/span><\/p>\n

Characters in an individual range must occur in the natural order as they appear in the character set.
\nFor example, [f-a] will match nothing.<\/span><\/p>\n

Lists of characters, and one or more ranges of characters,<\/strong> may be intermixed<\/strong> in a single class definition. The start and end of a range may be specified by a literal character, or one of the backslash escape sequences:<\/p>\n

\\ – ] e f n q r t v x##<\/span><\/p>\n

Any other use of a backslash within a class definition yields an undefined operation.<\/p>\n

Multiple ranges in a class<\/strong><\/span> are valid.
\nFor example, [a-d2-5] matches a, b, c, d, 2, 3, 4, or 5.<\/span><\/p>\n

When the hyphen is escaped<\/strong>, it is treated as a literal.
\nFor example, [a-c] is a list, not a range, and matches a, -, or c due to the backslash escape sequence.<\/span><\/p>\n

[^] (caret)<\/strong> When the caret appears as the first item in a class definition, it identifies a complemented class of characters, which will not match.
\nFor example, [^abc] matches any character except a, b, or c.<\/span><\/p>\n

A range can also be specified for the complemented class. For example, [^a-z] matches any character except a through z.<\/p>\n

A caret located in any position other than the first is treated as a literal character.<\/p>\n

Tags\/sub-patterns<\/span><\/strong><\/p>\n

( ) (parentheses)<\/strong> : Parentheses are used to match a Tag, or sub-pattern, within the full search pattern, and remember the match. The matched sub-pattern can be retrieved later in the mask, or in a replace operation, with \u00001 through 99, based upon the left-to-right position of the opening parentheses.<\/p>\n

Parentheses may also be used to force precedence of evaluation with the alternation operator.
\nFor example, “(Begin)|(End)File” would match either “BeginFile” or “EndFile”,<\/span>
\nbut without the Tag designations,
\n“Begin|EndFile” would only match either “BeginndFile” or “BegiEndFile”.<\/span><\/p>\n

Note: Parentheses may not be used with ? + * as any match repetition could cause the tag value to be ambiguous.<\/span>
\nTo match repeated expressions, use parentheses followed by \u00001*.<\/span><\/p>\n

Escaped characters<\/span><\/strong><\/p>\n

(backslash)<\/strong>. The escape operator (single-character quote). The following character will be treated as a literal value rather than being interpreted as a special character. Note that the character following the backslash must actually be a special character, as follows:<\/p>\n

b A word boundary<\/strong>. The start or end of a word, where a word is defined as one or more characters that include an alphabetic character (A-Z or a-z), a numeric character (0-9), and an underscore.
\nFor example, “abc_123” is considered a single word and “abc-123” is considered two words.<\/span><\/p>\n

c Case-sensitive search.<\/strong> Without the c operator, the default is to ignore case when matching<\/span>. Unlike some other implementations of regular expressions, case-insensitivity is recognized in all operations, even a range of characters such as “[6-Z]”. The c operator may appear at any position in the mask.<\/p>\n

e Escape character:<\/p>\n

f\u00a0 Formfeed character:<\/p>\n

n Linefeed (or newline)<\/p>\n

q Double-quote mark (“):
\nexample: “qHelloq”.<\/span><\/p>\n

r Carriage-return character<\/p>\n

s Shortest match character:<\/strong> The s flag causes the shortest matching string to be returned, rather than the longest (the default)<\/span>.
\nFor example, when searching for the mask “abc.*abc” in “abcdabcabc”, the default setting would return position 1 and length 10. With the s switch set, it returns position 1 and length 7. This option may cause a slight increase in processing time.<\/span><\/p>\n

t Horizontal tab character<\/p>\n

v Vertical tab character<\/p>\n

x## Hex character code:<\/strong> Indicates that an ASCII code follows, given by two hexadecimal digits.
\nFor example, xFF = ANSI 255. XX must be in the range 0 through 255.<\/span><\/p>\n

## Tag number:<\/strong> Evaluated as the characters matched by tag number ## (where ## is in the range 01 through 99<\/span>, in decimal). Tags are implicitly numbered from 01 through 99, based upon the left-to-right position<\/span> of the left parenthesis. “(\ufffd)w\u00001” would match “abcwabc” or “456w456”.<\/span><\/p>\n

Tags cannot be forward-referenced – that is, if a reference is made to any Tag that is not yet defined, a non-match is presumed.<\/p>\n","protected":false},"excerpt":{"rendered":"

Using Regular Expressions in MarcEditor Replacement Functions: Regular Expressions can now be utilized in the Replace and Edit Subfield functions in the MarcEditor. This allows users to create complex search and replacement functions. In...<\/p>\n","protected":false},"author":1,"featured_media":2850,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[22],"tags":[84],"youtube_video":null,"_links":{"self":[{"href":"https:\/\/www.extradrm.com\/index.php?rest_route=\/wp\/v2\/posts\/285"}],"collection":[{"href":"https:\/\/www.extradrm.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.extradrm.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.extradrm.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.extradrm.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=285"}],"version-history":[{"count":0,"href":"https:\/\/www.extradrm.com\/index.php?rest_route=\/wp\/v2\/posts\/285\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.extradrm.com\/index.php?rest_route=\/wp\/v2\/media\/2850"}],"wp:attachment":[{"href":"https:\/\/www.extradrm.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=285"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.extradrm.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=285"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.extradrm.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=285"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}