SAS P1 L3c

Question 1

How are SAS Data sets set up?
table =?
column =?
row=?

Answer 1

SAS Data sets:
table = data set
column = variable
row = observation

Question 2

What is a variable?

Answer 2

Variable = container that stores values

Question 3

Parts of a data set?

Answer 3

Data sets have:

• descriptor portion
• data portion

Question 4

What is in descriptor portion of data set?

Answer 4

Descriptor portion of data set has
info about attributes of data set
"meta data"
general properties
data set name
when created
variable names

Question 5

What are data set values?

Answer 5

Data values can either be character or numeric.

Question 6

Write code:
How see descriptors for orion.sales?
How see data values for orion.sales?

Answer 6

Descriptors:
PROC CONTENTS data=orion.sales;
RUN;

Data values:
PROC PRINT data=orion.sales;
RUN;

Question 7

Alignments:
Character values?
Numeric values?

Answer 7

Character variables: Left aligned

Numeric variables: Right aligned

Question 8

What is a missing value?

Why does it exist?

Answer 8

Missing values:

• in SAS data sets, a value must exist for every variable and observation.
• if data value is unknown for particular observation, a “missing value” is recorded instead.
• the variable type determines what is recorded.

Question 9

What is seen if missing values is
character?
numeric?
Can they be altered?

Answer 9

Missing values:
character = blank
numeric = . (period)
These are default; can be altered via
MISSING='character'

Question 10

Are missing values valid values in SAS data sets?

Answer 10

Yes

Question 11

What are 2 kinds of SAS variable attributes?

Answer 11

SAS variable attributes:

type and length

Question 12

What is included in character type of attribute?

Answer 12

characters can be letters, numbers, special char, blanks

Question 13

What is included in numeric type of attribute?

Answer 13

numeric type can only be numeric values, including:
“-“ for negative
“E” for scientific notation
“.” single decimal point

Question 14

What is length?
length for Character?
length for Numeric?

Answer 14

Length = LEN
# of bytes used to store data
Length is related to variable type
CHARACTER = 1 to 32,767 bytes
1 byte = 1 character
NUMERIC = 8 bytes by default
stored as floating point or binary => 16 or 17 significant digits

Question 15

Are there other variable attributes?

Answer 15

yes, ex: format, etc – will learn later

Question 16

SAS naming conventions: Variable names?
length?
start?
contain?
case?
appearance in reports?

Answer 16

Variable names SAME as data set names:

• 1 to 32 characters long
• start with letter or underscore
• continue with any combo of #, letter, underscore
• any case (upper, lower mixed)
• SAS creates any variable name in the same case when you first specify it => how it will appear in reports
• but can refer to it in any way in code without affecting anything

Question 17

SAS naming conventions: Data set names?
length?
start?
contain?
case?
appearance in reports?

Answer 17

SAME as variable names:

• 1 to 32 characters long
• start with letter or underscore
• continue with any combo of #, letter, underscore
• any case (upper, lower mixed)
• SAS creates any variable name in the same case when you first specify it => how it will appear in reports
• but can refer to it in any way in code without affecting anything
• extra info about special char in variable names