I have two datasets in SAS that I would like to merge, but they have no common variables. One dataset has a "subject_id" variable, while the other has a "mom_subject_id" variable. Both of these variables are 9-digit codes that have just 3 digits in the middle of the code with common meaning, and that's what I need to match the two datasets on when I merge them.
What I'd like to do is create a new common variable in each dataset that is just the 3 digits from within the subject ID. Those 3 digits will always be in the same location within the 9-digit subject ID, so I'm wondering if there's a way to extract those 3 digits from the variable to make a new variable.
Thanks!
SQL(using sample data from Data Step code):
proc sql;
create table want2 as
select a.subject_id, a.other, b.mom_subject_id, b.misc
from have1 a JOIN have2 b
on(substr(a.subject_id,4,3)=substr(b.mom_subject_id,4,3));
quit;
Data Step:
data have1;
length subject_id $9;
input subject_id $ other $;
datalines;
abc001def other1
abc002def other2
abc003def other3
abc004def other4
abc005def other5
;
data have2;
length mom_subject_id $9;
input mom_subject_id $ misc $;
datalines;
ghi001jkl misc1
ghi003jkl misc3
ghi005jkl misc5
;
data have1;
length id $3;
set have1;
id=substr(subject_id,4,3);
run;
data have2;
length id $3;
set have2;
id=substr(mom_subject_id,4,3);
run;
Proc sort data=have1;
by id;
run;
Proc sort data=have2;
by id;
run;
data work.want;
merge have1(in=a) have2(in=b);
by id;
run;
an alternative would be to use
proc sql
and then use a join and the substr() just as explained above, if you are comfortable with sql
Assuming that your "subject_id" variable is a number then the substr function wont work as sas will try convert the number to a string. But by default it pads some paces on the left of the number.
You can use the modulus function mod(input, base) which returns the remainder when input is divided by base.
/*First get rid of the last 3 digits*/
temp_var = floor( subject_id / 1000);
/* then get the next three digits that we want*/
id = mod(temp_var ,1000);
Or in one line:
id = mod(floor(subject_id / 1000), 1000);
Then you can continue with sorting the new data sets by id and then merging.
Related
Dataset HAVE includes id values and a character variable of names. Values in names are usually missing. If names is missing for all values of an id EXCEPT one, the obs for IDs with missing values in names can be deleted. If names is completely missing for all id of a certain value (like id = 2 or 5 below), one record for this id value must be preserved.
In other words, I need to turn HAVE:
id names
1
1
1 Matt, Lisa, Dan
1
2
2
2
3
3
3 Emily, Nate
3
4
4
4 Bob
5
into WANT:
id names
1 Matt, Lisa, Dan
2
3 Emily, Nate
4 Bob
5
I currently do this by deleting all records where names is missing, then merging the results onto a new dataset KEY with one variable id that contains all original values (1, 2, 3, 4, and 5):
data WANT_pre;
set HAVE;
if names = " " then delete;
run;
data WANT;
merge KEY
WANT_pre;
by id;
run;
This is ideal for HAVE because I know that id is a set of numeric values ranging from 1 to 5. But I am less sure how I could do this efficiently (A) on a much larger file, and (B) if if I couldn't simply create an id KEY dataset by counting from 1 to n. If your HAVE had a few million observations and your id values were more complex (e.g., hexadecimal values like XR4GN), how would you produce WANT?
You can use SQL here easily, MAX() applies to character variables within SQL.
proc sql;
create table want as
select id, max(names) as names
from have
group by ID;
quit;
Another option is to use an UPDATE statement instead.
data want;
update have (obs=0) have;
by ID;
run;
This seems like a good candidate for a DOW-loop, assuming that your dataset is sorted by id:
data want;
do until(last.id);
set have;
by id;
length t_names $50; /*Set this to at least the same length as names unless you want the default length of 200 from coalescec*/
t_names = coalescec(t_names,names);
end;
names = t_names;
drop t_names;
run;
proc summary data=have nway missing;
class id;
output out=want(drop=_:) idgroup(max(names) out(names)=);
run;
Use the UPDATE statement. That will ignore the missing values and keep the last non-missing value. It normally requires a master and transaction dataset, but you can use your single dataset for both.
data want;
update have(obs=0) have ;
by id;
run;
I need to outline a series of ID numbers that are currently available based on a data set in which ID's are already assigned (if the ID is on the file then its in use...if its not on file, then its available for use).
The issue is I don't know how to create a data set that displays ID numbers which are between two ID #'s that are currently on file - Lets say I have the data set below -
data have;
input id;
datalines;
1
5
6
10
;
run;
What I need is for the new data set to be in the following structure of this data set -
data need;
input id;
datalines;
2
3
4
7
8
9
;
run;
I am not sure how I would produce the observations of ID #'s 2, 3 and 4 as these would be scenarios of "available ID's"...
My initial attempt was going to be subtracting the ID values from one observation to the next in order to find the difference, but I am stuck from there on how to use that value and add 1 to the observation before it...and it all became quite messy from there.
Any assistance would be appreciated.
As long as your set of possible IDs is know, this can be done by putting them all in a file and excluding the used ones.
e.g.
data id_set;
do id = 1 to 10;
output;
end;
run;
proc sql;
create table need as
select id
from id_set
where id not in (select id from have)
;
quit;
Create a temporary variable that stores the previous id, then just loop between that and the current id, outputting each iteration.
data have;
input id;
datalines;
1
5
6
10
;
run;
data need (rename=(newid=id));
set have;
retain _lastid; /* keep previous id value */
if _n_>1 then do newid=_lastid+1 to id-1; /* fill in numbers between previous and current ids */
output;
end;
_lastid=id;
keep newid;
run;
Building on Jetzler's answer: Another option is to use the MERGE statement. In this case:
note: before merge, sort both datasets by id (if not already sorted);
data want;
merge id_set (in=a)
have (in=b); /*specify datasets and vars to allow the conditional below*/
by id; /*merge key variable*/
if a and not b; /*on output keep only records in ID_SET that are not in HAVE*/
run;
I have 2 variables and 3 records in a sas data set, and based on the date field in that data set, I need to read different monthly data sets.
For example,
I have
item no. Date
1 30Jun2015
2 31Jul2015
3 31Aug2015
When I read the first record, then based on the date field (30jun2015) here, it should merge another dataset suffixed with 30jun2015 with this current dataset.
How can I achieve that?
So as I'll hazard a guess what you're looking for I've left a bit of a gap where you'll have to specifiy the criteria for your own merge.
1) Read in base data
data MAIN_DATA;
infile cards;
input ITEM_NO DATE:date9.;
format DATE date9.;
cards;
1 30JUN2015
2 31JUL2015
3 31AUG2015
;
run;
2) Store all dates: into macro variables date1 to daten. Assuming ddmmyy6. is a good format for your table names
Data _null_;
Set Main_data;
Call symputx('date'||strip(_n_),put(DATE,ddmmyy6.));
Call symputx('daten', _n_);
Run;
3) Read in the variables and read the associated table - you haven't specified how to do the merge so I'll leave that up to you
%macro readin;
%do i = 1 %to &daten;
data NEW_TABLE_&&date&i..;
set TEST_&&date&i..; /*in this step you can merge on the original table however you intend to*/
run;
%end;
%mend readin;
%readin;
I have a sas data set with 564 variables. I need to create a new table with three columns, column1 will be the variables name , column2 will be the value of that variable, and column3 will be observation number.
So if I have a variable gender then gender will be listed 2 times in the variable column, and the gender values will be listed as m in the first row and female in the second row, and the column3 will be just the number of the observation. This is how it should look. Many thanks in advance.
var value obs
gender m 1
gender f 2
ans yes 3
ans no 4
The key to getting a table out of PROC FREQ that has all the values in one column is ods output combined with coalescec.
ODS OUTPUT lets you tell PROC FREQ to put everything into one dataset (as opposed to out= which just puts one Freq table into one dataset). That gives you a slightly messy result, which we then use coalescec to fix. That function takes a list of variables and returns the first nonmissing value from them; since the F_ variables always have just one value populated (the formatted value of the variable in the table), it's easy to use them.
ods output onewayfreqs=freqs;
proc freq data=sashelp.class;
tables age sex;
run;
ods output close; *technically unneeded but makes it more clear;
data want;
set freqs;
value = left(coalescec(of f_:));
run;
The rest of what you note above is trivial from that dataset.
So I have multiple continuous variables that I have used proc rank to divide into 10 groups, ie for each observation there is now a "GPA" and a "GRP_GPA" value, ditto for Hmwrk_Hrs and GRP_Hmwrk_Hrs. But for each of the new group columns the values are between 1 - 10. Is there a way to change that value so that rather than 1 for instance it would be 1.2-2.8 if those were the min and max values within the group? I know I can do it by hand using proc format or if then or case in sql but since I have something like 40 different columns that would be very time intensive.
It's not clear from your question if you want to store the min-max values or just format the rank columns with them. My solution below formats the rank column and utilises the ability of SAS to create formats from a dataset. I've obviously only used 1 variable to rank, for your data it will be a simple matter to wrap a macro around the code and run for each of your 40 or so variables. Hope this helps.
/* create ranked dataset */
proc rank data=sashelp.steel groups=10 out=want;
var steel;
ranks steel_rank;
run;
/* calculate minimum and maximum values per rank */
proc summary data=want nway;
class steel_rank;
var steel;
output out=want_min_max (drop=_:) min= max= / autoname;
run;
/* create dataset with formatted values */
data steel_rank_fmt;
set want_min_max (rename=(steel_rank=start));
retain fmtname 'stl_fmt' type 'N';
label=catx('-',steel_min,steel_max);
run;
/* create format from previous dataset */
proc format cntlin=steel_rank_fmt;
run;
/* apply formatted value to rank column */
proc datasets lib=work nodetails nolist;
modify want;
format steel_rank stl_fmt10.;
quit;
In addition to Keith's good answer, you can also do the following:
proc rank data = sashelp.cars groups = 10 out = test;
var enginesize;
ranks es;
run;
proc sql ;
select *, catx('-',min(enginesize), max(enginesize)) as esrange, es from test
group by es
order by make, model
;
quit;