A Guide to Non-Alphanumeric Characters

Alphanumeric is a description of characters that is both letters and numbers. Typically you will see this term when setting a username on a website or elsewhere- when there is a restriction around the characters you are able to use. ‘1ffcs3rf1a’ is an example of a an alphanumeric string.

What about Non-Alphanumeric Characters ?

Then there are the non-alphanumeric characters, and the reason for this short article. Non-Alphanumeric characters are the other characters on your keyboard that aren’t letters or numbers, e.g. commas, brackets, space, asterisk and so on. Any character that is not a number or letter (in upper or lower case) is non-alphanumeric. These could be grouped as Punctuation characters  ! @ # & ( ) – [ { } ] : ; ', ? / * and symbol characters ` ~ $ ^ + = < > “.

Increasingly, non alphanumeric characters come into our conversations as we are using code to do more and more things. For example, talking about infrastructure as code templates, terraform plans, scripts and json files. Here is some json code for example, from an Azure ARM template:

 {
      "type": "Microsoft.Sql/servers/databases",
      "apiVersion": "2020-02-02-preview",
      "name": "[variables('databaseName')]",
      "location": "[parameters('location')]",
      "sku": {
        "name": "Basic",
        "tier": "Basic",
        "capacity": 5
      },
      "dependsOn": [
        "[resourceId('Microsoft.Sql/servers', variables('sqlServerName'))]"
      ],
      "tags": {
        "displayName": "[variables('databaseName')]"
      }

Now you need to know your curly brackets (braces) from your squiggly lines (tilde), so here is a handy list of the non alphanumeric character:

~	tilde
`	backtick
{	open brace
}	close brace
[	open bracket
]	close bracket
!	exclamation mark
%	percent
^	carat
*	asterisk
–	hyphen
=	equals
+	plus
_	underscore
|	pipe
\	backslash
/	forward slash
@	at
:	colon
;	semicolon
<	less than
>	greater than
?	question mark
.	period
,	comma
#	pound
&	ampersand
$	dollar
(	open parenthesis
)	close parenthesis