topic Re: problem of verify function in SAS Programming

problem of verify function

harrylui — Mon, 02 Mar 2020 08:47:04 GMT

good day,

I am using verify function to check similarity of my data. but the result looks odd to me.

Obs	name	lag_name	checking
1	Harry		1
2	Harry	Harry	6
3	Henry	Harry	2
4	Ben	Henry	1

seems blank also count one character

is the sequence matter here because

obs 3 should got 3 match word

obs 4 should got 2 match word

can anyone help me on that?

below is my program

data testing;
input name $40.;
infile datalines dlm=',';
datalines;
Harry
Harry
Henry
Ben
;
run;

data testing2;
set testing;
lag_name=compress(lag(name));
name2=compress(name);
run;

data checking;
set testing2;
checking=VERIFY(name2,lag_name);
run;

thanks in advance

harry

Re: problem of verify function

ed_sas_member — Mon, 02 Mar 2020 08:57:56 GMT

Hi @harrylui

Here is the output I get when I run the code using the VERIFY() function:

This function returns the position of the first character in the string that is not in any of several other strings, so the results seems good:

- H compared to a blank in first position

- Second record -> strings are strictly identical so no position is returned (0)

- e compared to a in second position

- B compared to a blank in first position

Depending on what you're trying to achieve, maybe you could explore the COMPGED() function. This function returns the generalized edit distance between two strings, i.e. the largest the distance is, the less similar the strings are. It is up to you to determine the threshold to determine "acceptable similarity". Zero indicates that strings are strictly identical.

data checking;
set testing2;
checking=compged(name2,lag_name);
run;

Hope this helps,

Best,

Re: problem of verify function

akanshya142 — Mon, 02 Mar 2020 09:02:26 GMT

The verify function will check the location where your string1 mismatches string2.

So in your example

Henry and Harry the letter H matches with H, but the 2nd letter e does not match with a. So the verify function returns 2.

For Ben and Henry, the 1st letter itself does not match, so the function returns 1.

Re: problem of verify function

harrylui — Tue, 03 Mar 2020 02:04:39 GMT

thanks all for the explanations