Character Class Functions

Octave also provides the following character class test functions patterned after the functions in the standard C library. They all operate on string arrays and return matrices of zeros and ones. Elements that are nonzero indicate that the condition was true for the corresponding character in the string array. For example

     isalpha ("!Q@WERT^Y&")
          => [ 0 1, 0, 1, 1, 1, 1, 0, 1, 0 ]
     

isalnum (s)

Mapping Function

Return 1 for characters that are letters or digits (isalpha (s) or isdigit (s) is true).

isalpha (s)	Mapping Function
isletter (s)	Mapping Function

Return true for characters that are letters (isupper (s) or islower (s) is true).

isascii (s)

Mapping Function

Return 1 for characters that are ASCII (in the range 0 to 127 decimal).

iscntrl (s)

Mapping Function

Return 1 for control characters.

isdigit (s)

Mapping Function

Return 1 for characters that are decimal digits.

isgraph (s)

Mapping Function

Return 1 for printable characters (but not the space character).

islower (s)

Mapping Function

Return 1 for characters that are lower case letters.

isprint (s)

Mapping Function

Return 1 for printable characters (including the space character).

ispunct (s)

Mapping Function

Return 1 for punctuation characters.

isspace (s)

Mapping Function

Return 1 for whitespace characters (space formfeed, newline, carriage return tab, and vertical tab).

isupper (s)

Mapping Function

Return 1 for upper case letters.

isxdigit (s)

Mapping Function

Return 1 for characters that are hexadecimal digits.