XSLT Cookbook

Removing Specific Characters from a String

Problem

You want to strip certain characters (e.g., whitespace) from a string.

Solution

Use translate with an empty replace string. For example, the following code can strip whitespace from a string:

translate($input," 	
&xd;", "")

Discussion

translate( ) is a versatile string function that is often used to compensate for missing string-processing capabilities in XSLT. Here you use the fact that translate( ) will not copy characters in the input string that are in the from string but do not have a corresponding character in the to string.

You can also use translate to remove all but a specific set of characters from a string. For example, the following code removes all non-numeric characters from a string:

translate($string, 
          translate($string,'0123456789',''),'')

The inner translate( ) removes all characters of interest (e.g., numbers) to obtain a from string for the outer translate( ), which removes these non-numeric characters from the original string.

Sometimes you do not want to remove all occurrences of whitespace, but instead want to remove leading, trailing, and redundant internal whitespace. XPath has a built-in function, normalize-space( ), which does just that. If you ever needed to normalize based on characters other than spaces, then you might use the following code (where C is the character you want to normalize):

translate(normalize-space(translate($input,"C "," C")),"C "," C")

However, this transformation won’t work ...