topic Re: DO LOOP question in SAS Programming

DO LOOP question

tappu440 — Fri, 24 Feb 2017 05:44:13 GMT

1.Write a SAS program to solve the given problem using Do

Loop:

A new account was opened in the SBI with initial deposit of

Rs. 10,000/. SBI offers an interest rate of 4%. Find the balance

after 5 years. Also store the every year and the balance.

YEAR PRINCIPAL INTEREST AMOUNT

1 10,000 (P * R)/100 A = P + INTEREST

2 P (P * R)/100 A = A1 + INTEREST

2. In the previous program what if the interest was paid

quarterly.

3. Calculate the amount for the following :

Amount deposited = Rs. 5000/month.

Rate of interest = 6 %

Duration = 3 Years.

Interest added yearly.

Re: DO LOOP question

Reeza — Fri, 24 Feb 2017 05:57:01 GMT

Sorry, what's your question?

Re: DO LOOP question

tappu440 — Fri, 24 Feb 2017 06:03:32 GMT

hi I couldn't able to get the logic.
data new;
priciple=10000;
do i= 1 to 5;
retain priciple 0;
interest=(priciple*4)/100;
Amount=priciple+interest;
priciple=amount+interest
output;
end;
run;

Re: DO LOOP question

Kurt_Bremser — Fri, 24 Feb 2017 07:07:32 GMT

Read the log, and you'll find the error. It's THAT obvious, really.

BTW your retain statement makes no sense. As your datastep only undergoes one iteration, it has no effect.

Re: DO LOOP question

Shmuel — Fri, 24 Feb 2017 07:16:59 GMT

RETIAN is used to save data in memory uninitialized at reading input.

As you don't have input file nor sas dataset, you don't need use the retain.

Your example is:

YEAR  PRINCIPAL          INTEREST             AMOUNT
1     10,000            (P * R)/100       A = P + INTEREST
2       P               (P * R)/100       A = A1 + INTEREST

in 2nd year you add interest to A1, no to A - so it should be comulative.

So try next code:

data new;
priciple=10000;  
Amount = priciple;  /* starting amount */
do i= 1 to 5;
     interest=priciple*4/100;   /* parenthesis not needed */
     Amount=priciple+interest;
     output;
end;
run;

Re: DO LOOP question

Kurt_Bremser — Fri, 24 Feb 2017 07:48:14 GMT

Try this code:

data new;
format priciple interest amount 20.2;
priciple = 10000;
do i = 1 to 5;
  interest = priciple * 4 / 100;
  amount = priciple + interest;
  priciple = amount + interest;
  output;
end;
run;

proc print data=new noobs;
run;

Note how proper indentation and the use of spaces makes the code more readable

Note the semicolon before the output statement (was missing in your code and causing an error)

Note the omitted retain statement

Note the use of a numeric format to make the results more readable

The log:

16         data new;
17         format priciple interest amount 20.2;
18         priciple = 10000;
19         do i = 1 to 5;
20           interest = (priciple * 4) / 100;
21           amount = priciple + interest;
22           priciple = amount + interest;
23           output;
24         end;
25         run;

NOTE: The data set WORK.NEW has 5 observations and 4 variables.
NOTE: DATA statement used (Total process time):
      real time           0.17 seconds
      cpu time            0.00 seconds
      

26         
27         proc print data=new noobs;
28         run;

NOTE: There were 5 observations read from the data set WORK.NEW.
NOTE: The PROCEDURE PRINT printed page 1.
NOTE: PROCEDURE PRINT used (Total process time):
      real time           0.10 seconds
      cpu time            0.01 seconds

Clean and no extra NOTEs

The result:

priciple                interest                  amount    i

10800.00                  400.00                10400.00    1
11664.00                  432.00                11232.00    2
12597.12                  466.56                12130.56    3
13604.89                  503.88                13101.00    4
14693.28                  544.20                14149.09    5

You might consider dropping i from the dataset.

Re: DO LOOP question

Shmuel — Fri, 24 Feb 2017 07:56:42 GMT

@Kurt_Bremser, are you not adding the interest twice:

  amount = priciple + interest;
  priciple = amount + interest;

should it not be:

  amount = priciple + interest;
  priciple = amount;

Re: DO LOOP question

Kurt_Bremser — Fri, 24 Feb 2017 08:00:13 GMT

@Shmuel wrote:

@Kurt_Bremser, are you not adding the interest twice:
  amount = priciple + interest;
  priciple = amount + interest;
should it not be:
  amount = priciple + interest;
  priciple = amount;

I have to admit that I was not giving attention to the logic, just making the code syntactically correct and easy to read, as that was what caught my attention in the first place.

Re: DO LOOP question

Shmuel — Fri, 24 Feb 2017 08:11:25 GMT

May summarize up to now:

1) I agree with @Kurt_Bremser that identation is important in order that program will be more readable.

2) According to example, one could think that interest is fixed, the same each year,

than the code should be:

data new;
priciple=10000;  
Amount = priciple;  /* starting amount */
do i= 1 to 5;
     interest=priciple*4/100;   /* parenthesis not needed */
     Amount=priciple+interest;
     output;
end;
run;

In case, interset is to be calculated on comulative pricipe and yearly interests, than the code is:

data new;
priciple=10000;  
Amount = priciple;  /* starting amount */
do i= 1 to 5;
     interest=priciple*4/100;   /* parenthesis not needed */
     Amount=priciple+interest;
     output;
    pricipe = amount; 
end;
format pricipe amount interest comma8.2;
run;

Re: DO LOOP question

Kurt_Bremser — Fri, 24 Feb 2017 08:45:53 GMT

My preferred method for calculating amounts + interest is to use a simple multiplication, as that can be used to calculate a deliberately set number of years in one step:

amount = start * (1 + rate / 100) ** years;

Interest for a given year would then be

interest = (start * (1 +  rate / 100) ** (years - 1)) * rate / 100;

The code for the original problem would look like

data new;
format priciple amount interest 20.2;
priciple = 10000;
rate = 4;
do years = 1 to 5;
  amount = priciple * (1 + rate / 100) ** years;
  interest = (priciple * (1 +  rate / 100) ** (years - 1)) * rate / 100;
  output;
end;
run;

The nice thing about this is that one does not have to run through all years starting with 1. One could run the calculations for years 20 to 25 only, and get the correct values.

Re: DO LOOP question

Yavuz — Fri, 24 Feb 2017 10:22:11 GMT

excellent solutions, thanks for all

Re: DO LOOP question

nehalsanghvi — Fri, 24 Feb 2017 14:53:13 GMT

This looks like a SAS class quiz/test problem 😉

Re: DO LOOP question

Reeza — Fri, 24 Feb 2017 14:57:47 GMT

@nehalsanghvi wrote:

This looks like a SAS class quiz/test problem 😉

A literal copy and paste of the assignment 🙂

@Yavuz please mark one of the solutions provided as the correct answer

Re: DO LOOP question

Yavuz — Fri, 24 Feb 2017 16:58:51 GMT

Ok Reeza thank you for informing me.