Help using Base SAS procedures

Round Function Question

Accepted Solution Solved
Reply
Super Contributor
Posts: 318
Accepted Solution

Round Function Question

Hi Experts,

Would like to consult regarding the round function.

Given the value 123.456 for a, how come this turns out to be the value when I use the round function.

ROUND parameter

a = 123.456

Result
b = round(a,0.01)123.46 (ok)
b = round(a,0.02)123.46 (ok)
b = round(a,0.03)123.45 (?)
b = round(a,0.04)123.44 (?)
b = round(a,0.05)123.45 (?)
b = round(a,0.06)123.48 (?)
b = round(a,0.07)123.48 (?)
b = round(a,0.08)123.44 (?)
b = round(a,0.09)123.48 (?)

Is there a bug on the round function or is there something I am not aware on how it derives into these results. Thanks!


Accepted Solutions
Solution
‎10-18-2012 05:36 AM
Super Contributor
Posts: 644

Re: Round Function Question

The second number in the SAS round function specifies the units that should be rounded to, so for example round(123.456, .03) says round the number to the nearest multiple of .03 .  There are 4115.2 multiples of .03 in the number 123.456; rounding this to the nearest integer gives 4115 multiples.  Multiplying back correctly gives the resultant 123.45, and so for the other values of rounding unit.

Initial value

Rounding Unit

Number of Multiples

Multiples Rounded

Multiplied back

123.456

0.01

12345.6

12346

123.46

123.456

0.02

6172.8

6173

123.46

123.456

0.03

4115.2

4115

123.45

123.456

0.04

3086.4

3086

123.44

123.456

0.05

2469.12

2469

123.45

123.456

0.06

2057.6

2058

123.48

123.456

0.07

1763.657143

1764

123.48

123.456

0.08

1543.2

1543

123.44

123.456

0.09

1371.733333

1372

123.48

View solution in original post


All Replies
Solution
‎10-18-2012 05:36 AM
Super Contributor
Posts: 644

Re: Round Function Question

The second number in the SAS round function specifies the units that should be rounded to, so for example round(123.456, .03) says round the number to the nearest multiple of .03 .  There are 4115.2 multiples of .03 in the number 123.456; rounding this to the nearest integer gives 4115 multiples.  Multiplying back correctly gives the resultant 123.45, and so for the other values of rounding unit.

Initial value

Rounding Unit

Number of Multiples

Multiples Rounded

Multiplied back

123.456

0.01

12345.6

12346

123.46

123.456

0.02

6172.8

6173

123.46

123.456

0.03

4115.2

4115

123.45

123.456

0.04

3086.4

3086

123.44

123.456

0.05

2469.12

2469

123.45

123.456

0.06

2057.6

2058

123.48

123.456

0.07

1763.657143

1764

123.48

123.456

0.08

1543.2

1543

123.44

123.456

0.09

1371.733333

1372

123.48

Respected Advisor
Posts: 3,124

Re: Round Function Question

Wow, This is awesome! I did not know that. Learn some. Thanks a lot!

Haikuo

Super Contributor
Posts: 318

Re: Round Function Question

This is totally great explanation regarding the round function. I believe most are not also aware of this. Thank you very much! You have just expanded my knowledge! Smiley Happy

Super Contributor
Posts: 644

Re: Round Function Question

I can envisage there might be a situation where round(x, .02) or round(x, .05) might be required but I cannot imagine why anyone would want round(x, .03) or round(x, .07).  However, it is there if needed.  You can also round to other fractions like quarters, round(x, .25) or eighths, round(x, .125) etc.

Rounding a whole number by say .07 can yield unexpected results: round(123, .07) = 122.99 ( ! ).

milts, thanks for your comment.  Can you mark this answered?

☑ This topic is SOLVED.

Need further help from the community? Please ask a new question.

Discussion stats
  • 4 replies
  • 1206 views
  • 2 likes
  • 3 in conversation