fortran中常常需要提取字符串中可见字符的索引,下面是个小例子:
!============================================================= subroutine TrimIndex(InStr,LeftIndex,RightIndex,status) !------------------------------------------------------------ !---识别InStr中左右有效可见字符(33-126)的索引 !---如果status==0,则识别正确 !---吴徐平2013-07-20(wxp07@qq.com) !------------------------------------------------------------ Implicit None Character(Len =*),Intent( IN ) :: InStr Integer,Intent( INOUT)::LeftIndex,RightIndex,status !------------------------------------------------------------ Integer ::i !------------------------------------------------------------ LeftIndex=0 do i=1,LEN(InStr),1 if ((IACHAR(InStr(i:i)) >32 ).AND.(IACHAR(InStr(i:i)) <127) ) then LeftIndex=i !-左边有效可见字符(33-126)的索引 EXIT end if end do !------------------------------------------------------------ RightIndex=LEN(InStr)+1 do i=LEN(InStr),1,-1 if ((IACHAR(InStr(i:i)) >32 ).AND.(IACHAR(InStr(i:i)) <127 )) then RightIndex=i !-右边有效可见字符(33-126)的索引 EXIT end if end do !-------------------------- if ((LeftIndex>0 ).AND. (LeftIndex<=RightIndex) .AND. (RightIndex<=LEN(InStr)))then status=0 !-操作正确 else status=-1 !-操作有误 end if !-------------------------- end subroutine TrimIndex
下面是测试程序:
program TestTrimIndex !----------------------------------------- !测试TrimIndex的程序 !吴徐平 2013-07-20 !wxp07@qq.com !编译:gfortran TestTrimIndex.f90 !----------------------------------------- implicit none integer :: count !-命令行参数的个数 CHARACTER(len=24) :: InStr !命令行参数 Integer::LeftIndex,RightIndex,status,i !----------------------------------------- count = command_argument_count() !获取主程序命令行的输入参数的个数 !------------------------------------ if (count>0) then do i=1,count CALL get_command_argument(i, InStr) call TrimIndex(InStr,LeftIndex,RightIndex,status) if (status==0)then write(*,*)'<'//InStr//'>' write(*,*)'<'//InStr(LeftIndex:RightIndex)//'>' write(*,*)LeftIndex write(*,*)RightIndex end if end do else write(*,*) 'You should input an argument!' end if !------------------------------------ end program
上面的子程序常用来查找字符串中第一个和最后一个不是空格字符的索引.
有图有真相,如下: