Module 3: Creating and Managing Variables

Question 1

What format does SAS spit out for the following date formats: mmddyy10., mmddyy8., date9., and date7.?

Ex. mmddyy, mmddyyyy, Oct. _th

Answer 1

1) mmddyy10.=mm/dd/yyyy
2) mmddyy8.=mm/dd/yy
3) date9.=ddOctyyyy
4) date7.=ddOctyy

Question 2

What format does SAS spit out for the following date formats: julian7., worddate18., and weekdate29. ?

Answer 2

1)julian7.=yyyyjulian
2)worddate18.=month d, yyyy
3)weekdate29. weekday month d, yyyy

Question 3

T/F: You can manipulate dates with numeric symbols.

Ex. +, - , /, etc.

Answer 3

True: but only if it’s in numeric character format

Question 4

List some common and simple date functions

Ex. day()

Answer 4

1) day()
2) month()
3) year()
4) qtr()
5) weekday()
6) mdy(month,day,year)

Question 5

Why is the intnx() function useful and write general syntax.

Answer 5

It is used to help with incrementing dates.
var=intnx(‘incre’, varname, -1,1,0, daytoincrement)

daytoincrement= first day(1), end of month(‘E’) etc

Question 6

What format does SAS spit out for the following date formats: time8. and time12.?

Answer 6

1)time8.=hh:mm:ss
2)hh:mm:ss.ss

Question 7

What are the parameters for the dhms() function?

Ex. what’s inside the (x,y,x)

Answer 7

(day,hour,minutes, seconds)

Question 8

T/F: You can treat datetime functions like date values to do mathematical calculations.

Answer 8

False: You need to treat them as time values

Question 9

What does the ceilings and floor functions do?

Answer 9

1)ceil(): returns the smallest integer that is greater than or equal to the argument

2) floor(): returns the largest integer that is less than or equal to the argument

Question 10

What does the int function do?

Answer 10

int() returns the integer protion of a numeric value

Question 11

Write the syntax for round() for an integer number and for a decimal.

Answer 11

1) var=round(var,1)
2) var=round(var,0.01)

Question 12

Write the syntax for scan() and explain what it does.

Answer 12

scan(string,n,delimiter)
returns the nth word from a string/variable

Note: you can omitt the delimier and SAS assumes all can be delimiters

Question 13

What is the syntax for substr() and what does it do?

Answer 13

substr(string, position, n)
It extracts from a string starting from the postion to n length

Question 14

What does the length() function do?

Answer 14

Gives the length of a string, excluding trailing and leading blanks

Question 15

What does the trim(), strip(), left() and right() functions do?

Answer 15

1) trim() removes trailing blanks
2) strip() removes trailing leading blanks
3)left() moves blanks to be trailing
4)right() moves blanks to be leading

Question 16

What is the difference between cat(), cats(), and catx()?

Answer 16

1) cat() concats 2+ variables, leaving in trailing and leading blanks
2) cats() concats 2+ variables, removing blanks
3) catx() concats 2+, removing blanks, and puts in seperators

syntax: catx(seperator,var)

Question 17

What are the three functions to transform uppercase, lowercase, and propercase

Answer 17

upcase()
lowcase()
propcase()

Question 18

What does the index and find functions do?

Answer 18

1)index():searches for the first occurance and returns the postion of the first character
2)find(): same as index, but accepts third argument to indicate which column to start the search

Question 19

What does the tranwrd function do?

Answer 19

replaces or removes all occurances of a word in the character string
tranwrd(var,target, replacement)

Question 20

What does the compress function do?

Answer 20

removes all instances of specified characters

Question 21

What does the input() and put() functions do?

Answer 21

1) input() converts variables from character to numeric variables
2) put() converts variables from numeric to character variables