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Manual Reference Pages  - isalnum (3)

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NAME

isalnum,isalpha,iscntrl,isdigit,isgraph,islower, isprint,ispunct,isspace,isupper,isascii,isblank,isxdigit(3f) - [M_strings:COMPARE] test membership in subsets of ASCII set (LICENSE:PD)

CONTENTS

Synopsis
Description
Examples
Author
License

SYNOPSIS

Where "FUNCNAME" is one of the function names in the group, the functions are defined by

    elemental function FUNCNAME(onechar)
    character,intent(in) :: onechar
    logical              :: FUNC_NAME

DESCRIPTION

These elemental functions test if a character belongs to various subsets of the ASCII character set.

isalnum
	returns .true. if character is a letter (a-z,A-Z) or digit (0-9)
isalpha
	returns .true. if character is a letter and .false. otherwise
isascii
	returns .true. if character is in the range char(0) to char(127)
isblank
	returns .true. if character is a blank (space or horizontal tab).
iscntrl
	returns .true. if character is a delete character or ordinary control character (0x7F or 0x00-0x1F).
isdigit
	returns .true. if character is a digit (0,1,...,9) and .false. otherwise
isgraph
	returns .true. if character is a printable ASCII character excluding space
islower
	returns .true. if character is a miniscule letter (a-z)
isprint
	returns .true. if character is a printable ASCII character
ispunct
	returns .true. if character is a printable punctuation character (isgraph(c) && !isalnum(c)).
isspace
	returns .true. if character is a null, space, tab, carriage return, new line, vertical tab, or formfeed
isupper
	returns .true. if character is an uppercase letter (A-Z)
isxdigit
	returns .true. if character is a hexadecimal digit (0-9, a-f, or A-F).

EXAMPLES

Sample Program:

   program demo_isdigit

    use M_strings, only : isdigit, isspace, switch
    implicit none
    character(len=10),allocatable :: string(:)
    integer                       :: i
       string=[&
       & ’1 2 3 4 5 ’ ,&
       & ’letters   ’ ,&
       & ’1234567890’ ,&
       & ’both 8787 ’ ]
       ! if string is nothing but digits and whitespace return .true.
       do i=1,size(string)
          write(*,’(a)’,advance=’no’)’For string[’//string(i)//’]’
          write(*,*) &
          all(isdigit(switch(string(i))).or.isspace(switch(string(i))))
       enddo

    end program demo_isdigit

Expected output:

   For string[1 2 3 4 5 ] T
   For string[letters   ] F
   For string[1234567890] T
   For string[both 8787 ] F

AUTHOR

John S. Urban

LICENSE

Public Domain

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isalnum (3)

July 05, 2020

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