SAS P1 L8a

Question 1

What is another name for a raw data file?

Answer 1

Raw data file is also called a flat file

Question 2

What are characteristics of raw data files?
types? (3)
where located?
what per line? fields?
what software needed?

Answer 2

Raw data files:
can be text, CSV, ASCII files
external text file
one record per line, usually multiple fields per record
NOT software specific

Question 3

How are raw data files arranged?

Answer 3

Raw data files: fields are delimited or arranged in columns

Question 4

Fields in delimited raw data file:
order?
separated by?
widths?
column headings?
documentation?

Answer 4

Fields in delimited raw data file:

• in sequential order
• separated by spaces or special char (ex: comma)
• fields can be varying widths
• no column headings
• will have external documentation = record layout, explains values

Question 5

Fixed column file:
how fields ID’d?
field width?

Answer 5

Fixed column file:
- fields are ID’d by starting and ending column
- given field will begin in same column, have same width in every record
(not learning these here)

Question 6

What info needs to be specified for SAS to read raw data file? (3)

Answer 6

For SAS to read raw data file, for each field, must specify:

• location of data value in record
• name of SAS variable in which to store data
• type of SAS variable

Question 7

Name 3 techniques to read raw data files.
What data can they read?
How is data arranged?

Answer 7

Techniques to read raw data files:
list input: standard and/or non-standard data
separated by delimitor
column input: only standard data
in columns
formatted input: standard and/or non-standard data
in columns
I think we only use list input in this course.

Question 8

What is standard data?

Answer 8

Standard data: data SAS can read without any special instructions

Question 9

What is non-standard data?

Answer 9

Non-standard data:

• includes data like dates, or special characters (ex: $)
• SAS needs special instructions to read non-standard data

Question 10

How do you use data step to read raw data?
Commands / key words?
Use SET statement?
Example?

Answer 10

Using data step to read raw data file:
- use INFILE, INPUT
- DON’T use SET statement
Ex: DATA output-SAS-data-set-name;
INFILE ‘raw-data-file-name’;
INPUT specifications;
RUN;

Question 11

INFILE statement:

identifies?

Answer 11

INFILE statement identifies physical name and location of raw data file

Question 12

INPUT statement:
describes?
assigns?

Answer 12

INPUT statement:

• describes arrangement of values in raw data file
• assigns input statements to corresponding SAS var

Question 13

INFILE syntax:
if referencing macro variable?
if delimiter is comma?
what is default delim?

Answer 13

• use double quotes if referencing macro variable
  (ex: “{and}path/sales.csv” where {and} = ampersand)
• use dlm = ‘,’ if delimiter is comma
  or change to appropriate char
• default delimeter is space

Question 14

INPUT syntax:
what if variable is string?
what order?
names must?
include which variables?
skip any fields?

Answer 14

INPUT variable1 {$} variable2 {$} …. ;

• add {$} if variable is string
• specify variables in order in which they appear in data set
• must follow SAS naming conventions for variables
• must include variables for ALL data up to and including last field you want
• any remaining fields will be ignored
• can’t skip over fields