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# textutil::trim(n) 0.8 tcllib "Text and string utilities, macro processing"

## Name

textutil::trim - Procedures to trim strings

## Synopsis

- package require Tcl 8.5 9
- package require textutil::trim ?0.8?

- ::textutil::trim::trim string ?regexp?
- ::textutil::trim::trimleft string ?regexp?
- ::textutil::trim::trimright string ?regexp?
- ::textutil::trim::trimPrefix string prefix
- ::textutil::trim::trimEmptyHeading string

## Description

The package textutil::trim provides commands that trim strings using arbitrary regular expressions.

The complete set of procedures is described below.

::textutil::trim::trim string ?regexp?

  Remove in string any leading and trailing substring according to the regular expression regexp and return the result as a new string. This is done for all lines in the string, that is any substring between 2 newline chars, or between the beginning of the string and a newline, or between a newline and the end of the string, or, if the string contain no newline, between the beginning and the end of the string. The regular expression regexp defaults to "[ \\t]+".

::textutil::trim::trimleft string ?regexp?

  Remove in string any leading substring according to the regular expression regexp and return the result as a new string. This apply on any line in the string, that is any substring between 2 newline chars, or between the beginning of the string and a newline, or between a newline and the end of the string, or, if the string contain no newline, between the beginning and the end of the string. The regular expression regexp defaults to "[ \\t]+".

::textutil::trim::trimright string ?regexp?

  Remove in string any trailing substring according to the regular expression regexp and return the result as a new string. This apply on any line in the string, that is any substring between 2 newline chars, or between the beginning of the string and a newline, or between a newline and the end of the string, or, if the string contain no newline, between the beginning and the end of the string. The regular expression regexp defaults to "[ \\t]+".

::textutil::trim::trimPrefix string prefix

  Removes the prefix from the beginning of string and returns the result. The string is left unchanged if it doesn't have prefix at its beginning.

::textutil::trim::trimEmptyHeading string

  Looks for empty lines (including lines consisting of only whitespace) at the beginning of the string and removes it. The modified string is returned as the result of the command.

## Bugs, Ideas, Feedback

This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category textutil of the Tcllib Trackers. Please also report any ideas for enhancements you may have for either package and/or documentation.

When proposing code changes, please provide unified diffs, i.e the output of diff -u.

Note further that attachments are strongly preferred over inlined patches. Attachments can be made by going to the Edit form of the ticket immediately after its creation, and then using the left-most button in the secondary navigation bar.

## See Also

regexp(n), split(n), string(n)

## Keywords

prefix, regular expression, string, trimming

## Category

Text processing