The IsControlCharacter(char) command determines whether char is a control character.

If char is a control character, IsControlCharacter returns true. Otherwise, false is returned.

Note: A control character is a special non-printing character that is defined by the character set to which it belongs. For more information about control characters in Maple, see backslash.

If char is a string that contains more than one character, then all the characters in the string are tested. The command returns true if the condition is true of all characters in the input string. For the empty string, the tested condition is vacuously true.

The StringTools[IsControlCharacter] command is thread-safe as of Maple 15.

For more information on thread safety, see index/threadsafe.

$\mathrm{with}\left(\mathrm{StringTools}\right)\:$

$s≔\mathrm{convert}\left(\left[\mathrm{`\$`}\left(1..255\right)\right]\,\'\mathrm{bytes}\'\right)\:$

$\mathrm{length}\left(s\right)$

$255$

$\mathrm{Select}\left(\mathrm{IsControlCharacter}\,s\right)$

$''\backslash a\backslash b\backslash t\backslash n\backslash v\backslash f\backslash r\backslash e''$