Synopsis:

 Filter the string to include only the allowed characters

Description:

 FILTER(<allowed-chars>,<string>) - Asterisk 1.6 and later
 FILTER(<allowed-chars>|<string>) - Asterisk 1.4

Notes

• *CLI> show function FILTER

Return value

Returns the resulting string.

Examples

 exten => s,1,Set(foo=${FILTER(0-9,${cdrnum})}) - Asterisk 1.6 and later
 exten => s,1,Set(foo=${FILTER(0123456789|${cdrnum})}) - Asterisk 1.4

Note: ISDN (Q.931) only permits ASCII characters (more precisely: the IA5 character set) as CallerID name.

Starting with Asterisk 1.6.0, FILTER permits the use of a range, as well as hexadecimal (specified as \xNN), octal (specified as \0NNN), and the usual control characters (\t, \r, and \n). A literal dash may be used either by prefixing it with a backslash or by encoding it in hexadecimal (\x2d) or octal (\055). A literal comma can likewise be encoded as \x2C or \054.

See also

• Asterisk variables
• Asterisk functions

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• Asterisk - documentation of application commands