topic what is 'leading sign'? in SAS Programming

what is 'leading sign'?

tianerhu — Fri, 20 Aug 2021 19:22:54 GMT

The following statements are true about automatic conversion:

It produces a numeric missing value from any character value that does not conform to standard numeric notation(digits with an optional decimal point, leading sign, or scientific notation)

Re: what is 'leading sign'?

PaigeMiller — Fri, 20 Aug 2021 19:26:25 GMT

There is no context here, we don't know what SAS function or statement this is referring to, we don't even know it is referring to SAS. Can you please provide some context?

Re: what is 'leading sign'?

ballardw — Fri, 20 Aug 2021 19:37:15 GMT

I'm going out on a limb and guessing that means a + or - (minus) before the rest of the value

This sounds like a True/False question in a quiz or similar.

Re: what is 'leading sign'?

tianerhu — Fri, 20 Aug 2021 19:55:57 GMT

Thank you for your help.

Re: what is 'leading sign'?

tianerhu — Fri, 20 Aug 2021 19:58:09 GMT

Re: what is 'leading sign'?

PaigeMiller — Fri, 20 Aug 2021 20:26:36 GMT

It's still not clear to me what question is being asked, and if true/false is the desired answer.

Furthermore, I find this wording extremely confusing:

The following statements are true about automatic conversion:

It produces a numeric missing value from any character value that does not conform to standard numeric notation(digits with an optional decimal point, leading sign, or scientific notation)

Is "digits with an optional decimal point, leading sign, or scientific notation" being the conditions that "does not conform to standard numeric notation"? Or is "digits with an optional decimal point, leading sign, or scientific notation" being the conditions that DO conform to standard number notation?

All around, a horribly worded question, which I decline to spend more time on.

Re: what is 'leading sign'?

sbxkoenk — Fri, 20 Aug 2021 20:42:35 GMT

Hello @PaigeMiller ,

Unfortunately that extremely confusing wording is in the SAS documentation.

Here it is: https://go.documentation.sas.com/doc/en/pgmsascdc/v_015/lepg/n04koei84kuaodn1g21eyx4btome.htm

Click on:
Example: Use Automatic Type Conversions

and scroll a bit down to "Key Ideas" section.

As far as I know "digits with an optional decimal point, leading sign, or scientific notation" are standard numeric notation but the sentence is indeed written in such a way that one suspects the opposite. In other words, sentence is counter-intuitive to read.

Here's automatic conversion with a leading sign (a + sign):

data _NULL_;
a='+1.23';
b=a*1.0;
put b=;
run;

Kind regards,

Koen

Re: what is 'leading sign'?

tianerhu — Fri, 20 Aug 2021 20:52:02 GMT

Thank you for your answer.

Re: what is 'leading sign'?

tianerhu — Fri, 20 Aug 2021 20:53:07 GMT

sorry about that .

Re: what is 'leading sign'?

Tom — Fri, 20 Aug 2021 21:16:22 GMT

You can send feedback to the documentation team by clicking on the FEEDBACK link in the page header. They are very responsive.

I am not sure there is much confusion in the sentence you quoted.

It produces a numeric missing value from any character value that does not conform to standard numeric notation (digits with an optional decimal point, leading sign, or scientific notation).

How else would you describe a string that represents a number?

But if you can suggest clearer wording I am sure they would appreciate it.

Re: what is 'leading sign'?

tianerhu — Sun, 22 Aug 2021 00:48:56 GMT

Thank you for your help .

Re: what is 'leading sign'?

tianerhu — Sun, 22 Aug 2021 01:01:20 GMT

Could you tell me where is the feedback link ? I can not find it .

Re: what is 'leading sign'?

Tom — Sun, 22 Aug 2021 01:05:58 GMT

When reading any of the documentation pages it is in the upper right.

Re: what is 'leading sign'?

tianerhu — Sun, 22 Aug 2021 02:35:55 GMT

Your advise give me a big help , thanks .