StringSubstring - Cookbook - s c h e m a t i c s : c o o k b o o k

Accessing Substrings

Solution

R5RS substring is the most general solution. substring takes a string, a start index, and (optionally) an end index. For example:

> (substring "Hello, World!" 7)
"World!"
> (substring "Hello, World!" 0 5)
"Hello"
> (substring "Hello, World!" 7 12)
"World"

substring always allocates a new string.

If you have SRFI-13, you may find a more suitable function for getting a substring. First of all, substring/shared may return a string that shares storage with the original argument. SRFI-13 also defines a string-copy that takes start and end arguments, effectively making it a version of substring/shared that always allocates a new string. Finally, if you need to take a substring from the start or end of a string, string-take and string-drop allow you to make a substring by taking or omitting characters from the start of a string. string-take-right and string-drop-right do the same from the end of a string.

-- GordonWeakliem - 22 Apr 2004

CookbookForm
TopicType:	Recipe
ParentTopic:	StringRecipes
TopicOrder:	030

Current Rev: r1.5 - 09 Jun 2004 - 15:42 GMT - NoelWelsh, Revision History:Diffs | r1.5 | > | r1.4 | > | r1.3

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s c h e m a t i c s : c o o k b o o k

Accessing Substrings

Problem

Solution

Discussion