SAS P1 L2b

Question 1

What is an SAS comment?

Answer 1

SAS Comments:
text that is ignored during processing
but is written to log (when program runs)

Question 2

Uses for SAS comments?

Answer 2

• document purpose of program
• explain segments
• mark SAS code as non-executing => commenting out code

Can help test program in stages:
comment out error free code
test only desired sections

Question 3

What are the two types of comments?

Answer 3

2 types of comments:
Block comment
Comment Statement

Question 4

How write a Block Comment?
begin?
end?

Answer 4

Block Comment:
begins with “/” (forward slash-asterisk)
ends with “/” (asterisk-forward slash)

Question 5

Block comment:
length?
contain internal semicolons?
nested?
in column 1 or 2? why?

Answer 5

Block statement:
any length
CAN contain semicolons
CANNOT be nested
NO block comments in column 1 or 2 - some editors read as code -> request to end job

Question 6

How write Comment Statement?
begin?
end?

Answer 6

Comment statement:
begins with “*” (asterisk)
followed by text of comment
ends with “;” (semicolon)

Question 7

Comment Statement:
length?
contain internal semicolons?
nested?
in column 1 or 2?

Answer 7

Comment Statement:
any length (?)
CANNOT contain internal semicolons
?nesting
CAN begin in columns 1 or 2

Question 8

Syntax errors are?

3 common ones?

Answer 8

Syntax errors are program statements that don’t conform to rules of SAS

Common:
misspelled key words
missing semicolon
invalid options

Question 9

How does editor indicate potential error?

Answer 9

Editor uses red to indicate potential errors

If data step has error, other steps following will also highlight since only work when in data step

Question 10

When are syntax errors found?

Answer 10

Syntax errors are found during compilation, before program is executed

Question 11

What does editor do if finds error? (3)

Answer 11

Editor will write:
- error or warning
- location
- explanation
Editor can also try to fix things - will show up in log

Question 12

What if error statement actually looks ok?

Answer 12

Error is underlined - if that statement looks ok, probably missing semicolon before

Question 13

What happens if unbalanced quotation marks?

Answer 13

Unbalance quotation marks:
Quotation mark counter keeps track
If detects uneven amount, won’t execute properly

Question 14

Can use single? Double? quotation marks?

Answer 14

Both single and double quotes can be used, but not as pair to each other

Question 15

Unbalanced quotation mark statement: appearance?

Answer 15

SAS will misread that statement and any following statements => will be colored purple = quoted string

Question 16

Unbalanced quotation mark statement: error warning?

Answer 16

NO ERROR WARNING

• banner will say “Data step still running”
• have to stop executing program by cancelling submitted statements

Question 17

Unbalanced quotation mark statement: where will see issue? What happens?

Answer 17

SAS Studio will write msg to log about error
“quoted string too long or ambiguous”

If see any log message about quoted string, look for unbalanced quotation mark

Will try to repair with wrapper code, code will stop running.