Extract substring of Fortran string array

Question

How does one extract a substring of a Fortran string array? For example

program testcharindex
    implicit none
    character(len=10), dimension(5) :: s
             


        

Answer 1

@francescalus has already explained the error, here's my contribution towards the question OP seems really to be tackling, ie how to read the integers from a string array such as

s = (/ '1_E ', '2_S ', '3_E ', '14_E', '25_S' /)

OP wants to do this without loops, and @roygvib points us towards using an elemental function. Here's my version of such a function to read the integer from a string. This ignores any leading spaces, so should cope with strings such as 12_e. It then stops scanning at the first non-digit character (so reads 12 from a string such as 12_3).

ELEMENTAL INTEGER FUNCTION read_int(str)
  CHARACTER(*), INTENT(in) :: str
  CHARACTER(:), ALLOCATABLE :: instr

  instr = adjustl(str)
  instr = instr(1:VERIFY(instr,'0123456789')-1)
  ! if the string doesn't have a leading digit instr will be empty, return a guard value
  IF(instr=='') instr = '-999'
  READ(instr,*) read_int
END FUNCTION read_int

I trust that this is clear enough. OP could then write

n = read_int(s)