CHARACTER: Specify and Initialize Character Strings

A character string is a contiguous sequence of bytes in memory. It must be specified before it is used in the script.

• see also Strings for more examples
• defining_a_string
  :
  • CHARACTER [::] string[*length] [/"inistring"/] [="inistring"] ! [ ] optional
  • length = a numerical constant known at compile time ( "Init, "Defi) to assign the byte count to string, default is 1
  • inistring = a string constant like "hello world"
  • examples:
    • REAL, PARAMETER :: n=100 ! predefines a symbolic constant
    • CHARACTER :: StringName*n
    • CHARACTER StringName='initialization string defines length'
    • CHARACTER StringName * n /"initialization string of length n"/
    • CHARACTER StringName*123 = "initialization string of length 123"
    • CHARACTER :: a, b*2, c='xyz', d*n ! lengths are 1, 2, 3, 100 resp.
    • CHARACTER zoo*n, fish='eel', bird*20/'eagle'/
• string_delimiters
  : almost all non-alfanumeric and non-operator characters, e.g.:
  • CHARACTER a="double quote", b='single quote', c=%percent%, d=#number_sign#, e=.period.
  • CHARACTER special = ;string with "double and ' embedded single ' quotes" like this;
• dynamically_change_string_length
  :
  • ALLOCATE(string, new_string_length)
  • ALLOCATE is to expand a string only
  • to
    rename_or_shrink_a_string
    use the ALIAS function
  • • ALLOCATE (String, 2* LEN(String)) ! this doubles current length
• substring_definitions
  :
  • substring = string(byte_nr) ! to reference a single character of a string
  • substring = string(start : [end])
  • substring = string(4:z) ! starts at byte 4 and extends to the current value of z
  • substring = string(start : ) ! extends to end of string
  • ALIAS(string,start, substring, LEN(string)-start+1) ! substring shares memory with string byte start to byte end
  • substring = CHAR(2, 4, 'ABC DEF GHI JKL ') ! substring 2 out of 4 equal length substrings is "DEF "
  • EDIT(Text=string, Right='x', Mark1, Right='y', Parse=SubStringName)
• more examples:
  • string = 'ABC..xyz' ! assign a constant, fill with trailing blanks
  • textA(i : i+8) = textB
  • i = INDEX(OtherString, "Hello") ! find the location of "Hello"
  • length_of_string = Lengt(string)
  • trimmed_length_of_string = LEN_TRIM(string)