New field based on year and populated values

[Etoo12121]

Hi,

So I have the dataset below and want to create a new variable (Weight_to_use).

If year = 2017 then weight_to_use should be populated from Weight_17.

If year = 2018, then weight_to_use should be 135 from Weight_18.

etc. etc.

I'm not sure how to right this logic. Any ideas?

Year	ID	Weight_17	Weight_18	Weight_19	Weight_to_use
2017	1234	130	135	132
2018	3344	234	250	244
2019	9999	180	192	167

[ballardw · Accepted solution]

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@Etoo12121 wrote:

Hi,

So I have the dataset below and want to create a new variable (Weight_to_use).

If year = 2017 then weight_to_use should be populated from Weight_17.

If year = 2018, then weight_to_use should be 135 from Weight_18.

etc. etc.

I'm not sure how to right this logic. Any ideas?

Year	ID	Weight_17	Weight_18	Weight_19	Weight_to_use
2017	1234	130	135	132
2018	3344	234	250	244
2019	9999	180	192	167

---

data have;
  input Year	ID	$ Weight_17	Weight_18	Weight_19;
datalines;
2017	1234	130	135	132	 
2018	3344	234	250	244	 
2019	9999	180	192	167	 
;

data want;
   set have;
   array w (2017:2019) Weight_17	Weight_18	Weight_19;
   weighttouse=w[year];
run;

Please note the data step to provide an actual data set to work with.

The Array w uses the (lowerbound:upperbound) notation to describe the values used to access elements of the array. In this case 2017 corresponds to weight_17, 2018 to Weight_18, and 2019 to weight_19.

Then you use the year value in that define range to access the specific value from the array.

[Etoo12121]

Thank you @ballardw It got me exactly what I wanted.

[Reeza]

@ballardw has definitely provided the correct solution but you can also look into VVALUEX() if you'd like. It returns the value in a column, if you pass it the name of the column in question. 

   weight_to_use = vvaluex(catt('weight_', substrn(year, 3, 2)));

---

@Etoo12121 wrote:

Hi,

So I have the dataset below and want to create a new variable (Weight_to_use).

If year = 2017 then weight_to_use should be populated from Weight_17.

If year = 2018, then weight_to_use should be 135 from Weight_18.

etc. etc.

I'm not sure how to right this logic. Any ideas?

Year	ID	Weight_17	Weight_18	Weight_19	Weight_to_use
2017	1234	130	135	132
2018	3344	234	250	244
2019	9999	180	192	167

---

[Etoo12121]

Thank you @Reeza. I tried this and it worked like a charm. Fairly simple and to the point. Definitely learned something new today.