Create a column in SAS using a macro variable - sas

I am trying to create a column using the string value of a macro variable in SAS.
I have a dataset called want7 which has a column called 'ID'. I want to create a new dataset called want8 with a new column called 'ID1' by dynamically linking it to &string1 (as in the name of the column is linked to &string1) but the values of the column should equal the value of the 'ID' column in want7. How do I do this? Thanks in advance. I have only copied and pasted what I could write since I am relatively new to SAS.
%let string1 = ID1;
data want8; set want7;
/*Something like &string1 = ID*
run;

Using sashelp.class as an example (because it exists by default). Substitute as needed:
%let string1 = ID1;
data want8;
set sashelp.class;
&string1 = age ;
run;
This will reread the dataset. If you just want renames, look at the dataset option rename=. See SAS documentation: https://support.sas.com/documentation/cdl/en/lrcon/62955/HTML/default/viewer.htm#a000695119.htm

Related

Append new column to existing table using SAS

I have a do loop in which I do calculation on new variable and results are stored as additional column, this column-s (at each iteration) should be attached to the output table defined by macro.
Here on SO something similar has been asked but the answer is not acceptable, the last answer is not compatible with sas command but very close, getting incomplete script with following:
proc sql;
update &outlib..&out.
set var._iqr = b.&var._iqr
from &outlib..&out. as a
left join cal_resul as b
on a.id_client=b.id_client
and a.reference_date=b.reference_date;
quit;
Here is my attempt which works but very slow:
proc sql; create table &outlib..&out. as select * from &inlib..&in.; quit; /* the input is as a basis for output table */
proc sql; alter table &outlib..&out. add &var._iqr numeric; quit; /* create empty column to be filled at each iteration */
proc sql;
update &outlib..&out. as a
set &var._iqr=(select b.&var._iqr from cal_resul as b
where a.id_client=b.id_client
and a.reference_date=b.reference_date
and a.data_source=b.data_source);
quit;
Attempt 2:
This is somewhat faster:
proc sort data=cal_resul; by id_client reference_date data_source; run;
data &outlib..&out.;
update &outlib..&out. cal_resul;
by id_client reference_date data_source;
run;
Simple left join (adding new column into existing table is way faster) but with left join I did not figure out how I can update (always retain the same dataset) the &outlib..&out. at each iteration. Many thanks for any help;
If you want to ADD a variable to a dataset you will have to make a new dataset. (Your ALTER TABLE statement will create a new dataset and copy over all of the observations.)
Looks like your data has three key variables. So use those in merging the new data to the old.
For example to make a new variable in HAVE named EXAMPLE_IQR using the variable EXAMPLE in the dataset NEW you could use code like this. I have used macro variables to show how you might use those macro variables as the parameters to a macro. It sounds like you don't want the process to add new observations to the existing dataset so I have added a check for that using the IN= dataset option.
%let base=work.have;
%let indata=work.new;
%let var=example;
data &base ;
merge &base(in=inbase)
&indata(keep=id_client reference_date data_source &var
rename=(&var=&var._iqr)
)
;
by id_client reference_date data_source;
if inbase;
run;

How to obtain the number of records of a dataset in SAS

I want to count the number of records in a dataset in SAS. There is a function the make this thing in a simple way? I used R ed for obtain this information there was the length() function. Morover I need the number of record to compute some percetages so I need this value not in a table but in a value that can be used for other data step. How can I fix?
Thanks in advance
Here is another solution, using SAS dictionaries,
proc sql;
select nobs into: num_obs
from dictionary.tables
where libname = "WORK" and memname = "A"
;
quit;
It is easy to get the size of many datasets by modifying the above code,
proc sql;
create table test as
select memname, nobs
from dictionary.tables
where libname = "WORK" and memname like "A%"
;
quit;
data _null_;
set test;
call symput(memname, nobs);
run;
The above code will give you the sizes of all data sets with name starting with "a" in the temporary/work library.
Assuming this is a basic SAS table that you've created, and not modified or appended to, the best way is to use the meta data held in a dataset (the Number of tries is held in a piece of meta data called "nobs"), without reading through the dataset its self and place it in a macro variable. You can do this in the following way:
Data _null_;
i=1;
If i = 0 then set DATASETTOCOUNT nobs= mycount;
Call symput('mycount', mycount);
Run;
%put &mycount.;
You will now have a macro variable that contains the number of rows in your dataset, that you can call on in other data steps using &mycount.

I want to add auto_increment column in a table in SAS

I want to add a auto_Increment column in a table in SAS.Following code add's a column but not increment the value.
Thanks In Advance.
proc sql;
alter table pmt.W_cur_qtr_recoveries
add ID integer;
quit;
Wow, going to try for my second "SAS doesn't do that" answer this morning. Risky stuff.
A SAS dataset cannot define an auto-increment column. Whether you are creating a new dataset or inserting records into an existing dataset, you are responsible for creating any increment counters (ie they are just normal numeric vars where you have set the values to what you want).
That said, there are DATA step statements such as the sum statement (e.g. MyCounter+1) that make it easier to implement counters. If you describe more details of your problem, people could provide some alternatives.
The correct answer at this time is to create the ID yourself, BUT the discussion wouldn't be complete without mentioning that there is an unsupported SQL function Monotonic that can do what you want. It's not reliable, yet it persists.
The code pattern for its usage is
select monotonic() as ID, ....
Use the _N_ automatic variable in a data step like:
DATA TEMPLIB.my_dataset (label="my dataset with auto increment variables");
SET TEMPREP.my_dataset;
sas_incr_num = _N_; * add an auto increment 'sas_incr_num' variable;
sas_incr_cat = cat("AB.",cats(repeat("0",5-ceil(log10(sas_incr_num+1))),sas_incr_num),".YZ"); * auto increment the sas_incr_num variable and add 5 leading zeros and concatenate strings on either end;
LABEL
sas_incr_num="auto number each row"
sas_incr_cat="auto number each row, leading zeros, and add strings along for fun"
...
There is no such thing as an auto increment column in a SAS dataset. You can use a data step to create a new dataset that has the new variable. You can use the same name to have it replace the old one when done.
data pmt.W_cur_qtr_recoveries;
set pmt.W_cur_qtr_recoveries;
ID+1;
run;
It really depends on what your intended outcome is. But I have thrown together an example of how you may want to tackle this. it is a little rough, but gives you something to work from.
/*JUST SETTING UP THE DAY ONE DATA WITH AN ID ATTACHED
YOU WOULD MAKE THE FIRST RUN EXECUTE DIFFERENTLY TO SUBSEQUENT RUNS BY USING THE EXISTS FUNCTION AND MACRO LANGUAGE,
BUT I WILL LET YOU INVESTIGATE THIS FURTHER AS IT MAY BE IRRELEVANT.*/
DATA DAY1;
SET SASHELP.CLASS;
ID+1;
RUN;
/*ON DAY 2 WE ARE APPENDING ADDITIONAL RECORDS TO THE EXISTING DATASET*/
DATA DAY2;
/*APPEND DATASETS*/
SET DAY1 SASHELP.CLASS;
/*HOLD VALUE IN PROGRAM DATA VECTOR (PDV) UNTIL EXPLICITLY CHANGED*/
RETAIN _ID;
/*ADD VARIABLE _ID AND POPULATE WITH ID. IN DOING THIS THE LAST INSTANCE OF THE ID WILL BE HELD IN THE PDV FOR THE
FIRST OF THE NEW RECORDS*/
IF ID ~= . THEN _ID = ID;
/*INCREMENT THE VALUE IN _ID BY 1 AND DO SO FOR EACH RECORD ADDED*/
ELSE DO;
_ID+1;
END;
/*DROP THE ORIGINAL ID;*/
DROP ID;
/*RENAME _ID TO ID*/
RENAME _ID = ID;
RUN;
where "W_prv_qtr_recoveries" is a table Name and "pmt" is a library name.
Thanks to user2337871.
DATA pmt.W_prv_qtr_recoveries;
SET pmt.W_prv_qtr_recoveries;
RETAIN _ID;
IF ID ~= . THEN _ID = ID;
ELSE DO;
_ID+1;
END;
DROP ID;
RENAME _ID = ID;
RUN;
Assuming that this autoincrement column will be used for every record that is inserted.
We can accomplish the same as follows:-
We will first check the latest key in the dataset
PROC SQL;
SELECT MAX(KEY) INTO :MK FROM MYDATA;
QUIT;
%put KeyOld=&MK;
Then we increment this key
Data _NULL_;
call symput('KeyNew',&MK+1);
run;
%put KeyNew=&KeyNew;
Here we hold the New record that we want to insert, and add the correspoding key
Data TEMP1;
set TEMP;
Key=&KeyNew;
run;
Finally we load the new record in our dataset
PROC APPEND BASE=MYDATA DATA=TEMP1 FORCE;
RUN;

How to change the column headers of a sas dataset into an observation?

I have created a sas code which generates many sas datasets. Now I want to append all of them to a single excel file . So first I want to convert all the column headers of sas datasets as first observation. Then leave space between these datasets (adding a blank observation). How can we do it?
one way to do this would be to use dictionary.columns
proc sql;
create table Attribute as
select * from dictionary.columns;
Read through the table and check what attributes you are interested in. For your case you might be interested in the column "NAME" <- consist of the name of all columns.
Modify the table by adding where statement to the proc sql based on the identity of the column ( from which library / what type of file / name of file) e.g. where upcase(libname)= "WORK"
data attribute;
array column [ n ] $ length ;
do i=1 to n;
set attribute ( keep = name) ;
column [ i ] = name ;
end;
run;
Then I would proceed with data step. You could use macro variable to store the value of column's names by select variable into : but anyhow you still need to hardcode the size for the array n or any other method that store value into one observation . Also remember define the length and the type of array accordingly. You can give name to the variable in the result dataset Attribute by adding var1-varnafter the length at array statement.
For simplicity I use set statement to read observation one and one and store the value of column NAME, which is the official column name derived when using dictionary.columns into the array
Note that creating a non-temporary array would create variable(s) .
Add if you want to add the blank,
data younameit ;
merge attribute attribute(firstobs=2 keep=name rename=(name=_name));
output;
if name ne _name then do;
call missing(of _all_);
output;
end;
run;
As two datasets start with different observation and column names do not duplicate within one dataset, the next row of a valid observation ( derived from the first output statement in the resulting dataset would be empty due to call missing ( of _all_ ) ; output;
Sounds like you just want to combine the datasets and write the results to the Excel file. Do you really need the extra empty row?
libname out xlsx 'myfile.xlsx';
data out.report ;
set ds1 ds2 ...;
run;
Ensure that all your columns are character (or numeric, substitute numeric), then in your data step use:
array names{*} _character_;
do i=1 to dim(names);
call label(names{i}, names{i});
end;
output;

Keeping/Dropping Variables in SAS

I want to remove columns/variables from a large SAS dataset, call it 'data'. I have all of the column names that I want to drop stored in another SAS dataset - let's call it 'var', it has a single column with header column. How do I drop all of the variables contained in 'var' from my original dataset 'data' with the drop function?
Thanks!
You can use the "into" clause of proc sql to copy the column of variable names from the "vars" data set into a macro variable that you then pass to the drop= statement in a data step. See below:
proc sql noprint;
select <name_of_column> into: vars_to_drop separated by " "
from var;
quit;
data data;
set data (drop= &vars_to_drop);
run;