regreplace

Purpose

Replace portions of a text string based on a regular expression.

Synopsis

function regreplace(src:text, regex:string, repl:string):integer

function regreplace(src:text, regex:string, repl:string, start:integer, flags:integer):integer

Arguments

src

Text to process

regex

Regular expression

repl

Replacement string expression

start

Position where to start the search

flags

Search options:

REG_EXTENDED	Use Extended Regular Expression syntax (ERE), default is to interpret the expression as a Basic Regular Expression (BRE)
REG_ICASE	Comparison is performed case insensitive (by default it is case sensitive)
REG_NEWLINE	The character newline ( \n) is treated as the end of line (by default it is handled as an ordinary symbol)
REG_NOTBOL	The beginning of the text string is not the beginning of a line
REG_NOTEOL	The end of the text string is not the end of a line
REG_ONCE	Stop after the first replacement (by default the entire input string is processed)

Return value

The number of replacements performed.

Example

The following statement transforms dates expressed as year-month-day to dates in the form day/month/year

nbr:=regreplace(t,
      '([[:digit:]]{4})-([01]?[[:digit:]])-([0-3]?[[:digit:]])',
      '\3/\2/\1',1,REG_EXTENDED)

Further information

1. This function relies on the TRE library (see http://laurikari.net/tre). Please refer to the documentation of this library for a detailed description of the supported expression syntax.

2. In the replacement string repl the backslash character ( '\') has a special meaning: if followed by another baskslash character it is replaced by a single backslash; if followed by a digit it is replaced by the corresponding subexpression defined by the regular expression. The subexpression number 0 corresponds to the entire matching region.

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regreplace