Email Address Validation with PRXMATCH and FCMP

The script begins by creating a dataset named `test_email` containing a list of email addresses, some valid and some not, via `datalines`. Then, it defines a custom SAS^© function `CheckMail` using `PROC FCMP`. This function takes a character string (the email address) as input, converts it to lowercase, then uses the `PRXMATCH` regular expression to check if it matches a standard email address format. The validation result (0 if invalid, 1 if valid) is returned. Finally, a second `DATA STEP` is used to apply this `CheckMail` function to each email address in the `test_email` dataset and store the result in a new variable `Cmail`.

Data Analysis

Type : CREATION_INTERNE

The data is entirely created internally within the script via `datalines` in the first `DATA STEP`. The second `DATA STEP` uses the previously created dataset.

1 Code Block

DATA STEP Data

Explanation :
This `DATA STEP` block creates a temporary dataset named `test_email`. It reads email addresses provided directly in the script via `datalines`. The `email` variable is defined as a character with a maximum length of 32.

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1	DATA test_email;
2	informat email $32.;
3	INPUT email;
4	DATALINES;
5	test @test.fr
6	Test @test.fr
7	test @test..fr
8	.test @test.fr
9	.test @@test.fr
10	test @code_sas_json/marktest.json @test.fr
11	1.test @test.fr
12	n.test @test.fr
13	;
14	RUN;

2 Code Block

PROC FCMP

Explanation :
This `PROC FCMP` block defines a custom function named `CheckMail`. It is stored in the `work.cat_function` library under the `test` entry. The function takes an `Email` argument (character string), converts it to lowercase, then uses `PRXMATCH` with a regular expression to check the validity of the email address format. `PRXMATCH` returns the match position if found, or 0 otherwise. This result (0 or >0) is returned by the function.

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1	PROC FCMP outlib=work.cat_function.test ;
2	function CheckMail(Email $);
3	mail=Email;
4	res = prxmatch("/^" !!
5	"[a-z0-9#\$%&'*+\/=\]+?^_`\{\|\}~-]+" !!
6	"(?:\.[a-z0-9!#\$%&'+\/=\?^_`\{\|\}~-]+)" !!
7	" @" !!
8	"(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+" !!
9	"[a-z0-9]" !!
10	"(?:[a-z0-9-]*[a-z0-9])?" !!
11	"/"
12	,
13	lowcase(mail));
14	return(res);
15	endsub;
16	RUN;

3 Code Block

DATA STEP

Explanation :
This second `DATA STEP` reads the `test_email` dataset created previously. For each observation, it calls the `CheckMail` function with the email address and stores the validation result (0 or 1) in a new numeric variable `Cmail`.

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1	DATA test_email;
2	SET test_email;
3	Cmail=CheckMail(email);
4	RUN;

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Copyright Info : Creation date : 09/04/2017 (fr) Last update : 09/04/2017 (fr) Author(s) : Contributor(s) : Tested on SAS Studio 9.4

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