Info Catalog octave: String Conversions octave: Strings

octave: Character Class Functions

 
 5.7 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)
      Return a logical array which is true where the elements of S are
      letters or digits and false where they are not.
 
      This is equivalent to (‘isalpha (S) | isdigit (S)’).
 
      See also: isalpha XREFisalpha, isdigit XREFisdigit,
DONTPRINTYET       ispunct XREFispunct, isspace XREFisspace, *noteDONTPRINTYET       ispunct XREFispunct, isspace XREFisspace, 
      iscntrl XREFiscntrl.
 
  -- : isalpha (S)
      Return a logical array which is true where the elements of S are
      letters and false where they are not.
 
      This is equivalent to (‘islower (S) | isupper (S)’).
 
      See also: isdigit XREFisdigit, ispunct XREFispunct,
DONTPRINTYET       isspace XREFisspace, iscntrl XREFiscntrl, *noteDONTPRINTYET DONTPRINTYET       isspace XREFisspace, iscntrl XREFiscntrl, 
      isalnum XREFisalnum, islower XREFislower, *noteisupper:
DONTPRINTYET DONTPRINTYET       isspace XREFisspace, iscntrl XREFiscntrl, 
      isalnum XREFisalnum, islower XREFislower, isupper

      XREFisupper.
 
  -- : isletter (S)
      Return a logical array which is true where the elements of S are
      letters and false where they are not.
 
      This is an alias for the ‘isalpha’ function.
 
      See also: isalpha XREFisalpha, isdigit XREFisdigit,
DONTPRINTYET       ispunct XREFispunct, isspace XREFisspace, *noteDONTPRINTYET       ispunct XREFispunct, isspace XREFisspace, 
      iscntrl XREFiscntrl, isalnum XREFisalnum.
 
  -- : islower (S)
      Return a logical array which is true where the elements of S are
      lowercase letters and false where they are not.
 
      See also: isupper XREFisupper, isalpha XREFisalpha,
      isletter XREFisletter, isalnum XREFisalnum.
 
  -- : isupper (S)
      Return a logical array which is true where the elements of S are
      uppercase letters and false where they are not.
 
      See also: islower XREFislower, isalpha XREFisalpha,
      isletter XREFisletter, isalnum XREFisalnum.
 
  -- : isdigit (S)
      Return a logical array which is true where the elements of S are
      decimal digits (0-9) and false where they are not.
 
      See also: isxdigit XREFisxdigit, isalpha XREFisalpha,
DONTPRINTYET       isletter XREFisletter, ispunct XREFispunct, *noteDONTPRINTYET       isletter XREFisletter, ispunct XREFispunct, 
      isspace XREFisspace, iscntrl XREFiscntrl.
 
  -- : isxdigit (S)
      Return a logical array which is true where the elements of S are
      hexadecimal digits (0-9 and a-fA-F).
 
      See also: isdigit XREFisdigit.
 
  -- : ispunct (S)
      Return a logical array which is true where the elements of S are
      punctuation characters and false where they are not.
 
      See also: isalpha XREFisalpha, isdigit XREFisdigit,
      isspace XREFisspace, iscntrl XREFiscntrl.
 
  -- : isspace (S)
      Return a logical array which is true where the elements of S are
      whitespace characters (space, formfeed, newline, carriage return,
      tab, and vertical tab) and false where they are not.
 
      See also: iscntrl XREFiscntrl, ispunct XREFispunct,
      isalpha XREFisalpha, isdigit XREFisdigit.
 
  -- : iscntrl (S)
      Return a logical array which is true where the elements of S are
      control characters and false where they are not.
 
      See also: ispunct XREFispunct, isspace XREFisspace,
      isalpha XREFisalpha, isdigit XREFisdigit.
 
  -- : isgraph (S)
      Return a logical array which is true where the elements of S are
      printable characters (but not the space character) and false where
      they are not.
 
      See also: isprint XREFisprint.
 
  -- : isprint (S)
      Return a logical array which is true where the elements of S are
      printable characters (including the space character) and false
      where they are not.
 
      See also: isgraph XREFisgraph.
 
  -- : isascii (S)
      Return a logical array which is true where the elements of S are
      ASCII characters (in the range 0 to 127 decimal) and false where
      they are not.
 
  -- : isstrprop (STR, PROP)
      Test character string properties.
 
      For example:
 
           isstrprop ("abc123", "alpha")
           ⇒ [1, 1, 1, 0, 0, 0]
 
      If STR is a cell array, ‘isstrpop’ is applied recursively to each
      element of the cell array.
 
      Numeric arrays are converted to character strings.
 
      The second argument PROP must be one of
 
      "alpha"
           True for characters that are alphabetic (letters).
 
      "alnum"
      "alphanum"
           True for characters that are alphabetic or digits.
 
      "lower"
           True for lowercase letters.
 
      "upper"
           True for uppercase letters.
 
      "digit"
           True for decimal digits (0-9).
 
      "xdigit"
           True for hexadecimal digits (a-fA-F0-9).
 
      "space"
      "wspace"
           True for whitespace characters (space, formfeed, newline,
           carriage return, tab, vertical tab).
 
      "punct"
           True for punctuation characters (printing characters except
           space or letter or digit).
 
      "cntrl"
           True for control characters.
 
      "graph"
      "graphic"
           True for printing characters except space.
 
      "print"
           True for printing characters including space.
 
      "ascii"
           True for characters that are in the range of ASCII encoding.
 
      See also: isalpha XREFisalpha, isalnum XREFisalnum,
DONTPRINTYET       islower XREFislower, isupper XREFisupper, *noteDONTPRINTYET DONTPRINTYET       islower XREFislower, isupper XREFisupper, 
      isdigit XREFisdigit, isxdigit XREFisxdigit, *noteisspace:
DONTPRINTYET DONTPRINTYET DONTPRINTYET       islower XREFislower, isupper XREFisupper, 
      isdigit XREFisdigit, isxdigit XREFisxdigit, isspace

      XREFisspace, ispunct XREFispunct, *noteiscntrl:
DONTPRINTYET DONTPRINTYET DONTPRINTYET DONTPRINTYET       islower XREFislower, isupper XREFisupper, 
      isdigit XREFisdigit, isxdigit XREFisxdigit, isspace

      XREFisspace, ispunct XREFispunct, iscntrl

      XREFiscntrl, isgraph XREFisgraph, *noteisprint:
DONTPRINTYET DONTPRINTYET DONTPRINTYET DONTPRINTYET       islower XREFislower, isupper XREFisupper, 
      isdigit XREFisdigit, isxdigit XREFisxdigit, isspace

      XREFisspace, ispunct XREFispunct, iscntrl

      XREFiscntrl, isgraph XREFisgraph, isprint

      XREFisprint, isascii XREFisascii.
 

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