Counting unique observations in two datasets (merged by id)

ak2011 — Wed, 19 Feb 2020 03:56:03 GMT

Hi,

Can someone please help me with the code to count the number of unique lung subjects ( Ca case, Ca cont and Pop cont) in a merged dataset (Table 2). I would like to obtain the same number of Ca case(2 obs), Ca cont (3 obs) and Pop cont (4 obs) as shown in Table 1 Unique lung subject means one lung observation(eg. Ca case, Ca cont or Ca cont) for each id.

Eg. id OSa13 each has Ca case but actually the number of ca case for OSa13 is one (1).

Please find below the code and log. Output is attached. Thanks. ak.

/*  Cancer subjects*/
data d2;
input id$ 1-5 lung$ 7-15;
datalines;
OSa01 Pop cont
OSa06 Ca cont
OSa11 Pop cont
OSa13 Ca case
OSa29 Ca cont
OSa30 Ca case
OSa31 Ca cont
OSa54 Pop cont
OSa73 Pop cont
;
proc sort data=d2; by id; run;

proc freq data=d2;
tables lung;
Title "Table 1: Lung frequencies in d2";
run;

/* Exposure Duration*/
data d4;
input id$ 1-5 idchem 7-12 status$ 14-15 duration 16-18;
datalines;
OSa03 211701 S 6
OSa06 210701 S 9
OSa13 210701 S 37
OSa13 990005 S 5
OSa13 990021 S 37
OSa29 210701 NS 12
OSa29 990005 S 2
OSa30 210701 S 8
OSa30 211701 NS 8
OSa30 990005 S  8
OSa30 990021 S 15
OSa54 210701 NS 14
OSa64 210701 S 15
OSa74 211701 NS 21
OSa78 210701 NS 20
OSa78 990005 S 20
OSa78 990021 S 20
OSa86 990005 S 14
OSa93 210701 S 4
OSa93 990005 S 13
;

proc sort data=d4; by id; run;

/* Merging d2 & d4*/
data mg24;
merge d2(in=a) d4(in=b); by id;
if a and b;
run;

proc freq data=mg24;
tables lung;
title "Table 2: Lung frequencies in merged file d2,d4";
run;

1 OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK;

73 /* Cancer subjects*/

74 data d2;

75 input id$ 1-5 lung$ 7-15;

76 datalines;

NOTE: The data set WORK.D2 has 9 observations and 2 variables.

NOTE: DATA statement used (Total process time):

real time 0.01 seconds

cpu time 0.01 seconds

86 ;

87 proc sort data=d2; by id; run;

NOTE: There were 9 observations read from the data set WORK.D2.

NOTE: The data set WORK.D2 has 9 observations and 2 variables.

NOTE: PROCEDURE SORT used (Total process time):

real time 0.01 seconds

cpu time 0.01 seconds

89 proc freq data=d2;

90 tables lung;

91 Title "Table 1: Lung frequencies in d2";

92 run;

NOTE: There were 9 observations read from the data set WORK.D2.

NOTE: PROCEDURE FREQ used (Total process time):

real time 0.27 seconds

cpu time 0.25 seconds

94 /* Exposure Duration*/

95 data d4;

96 input id$ 1-5 idchem 7-12 status$ 14-15 duration 16-18;

97 datalines;

NOTE: The data set WORK.D4 has 20 observations and 4 variables.

NOTE: DATA statement used (Total process time):

real time 0.01 seconds

cpu time 0.00 seconds

118 ;

119

120 proc sort data=d4; by id; run;

NOTE: There were 20 observations read from the data set WORK.D4.

NOTE: The data set WORK.D4 has 20 observations and 4 variables.

NOTE: PROCEDURE SORT used (Total process time):

real time 0.20 seconds

cpu time 0.01 seconds

121

122 /* Merging d2 & d4*/

123 data mg24;

124 merge d2(in=a) d4(in=b); by id;

125 if a and b;

126 run;

NOTE: There were 9 observations read from the data set WORK.D2.

NOTE: There were 20 observations read from the data set WORK.D4.

NOTE: The data set WORK.MG24 has 11 observations and 5 variables.

NOTE: DATA statement used (Total process time):

real time 0.01 seconds

cpu time 0.02 seconds

127

128 proc freq data=mg24;

129 tables lung;

130 title "Table 2: Lung frequencies in merged file d2,d4";

131 run;

NOTE: There were 11 observations read from the data set WORK.MG24.

NOTE: PROCEDURE FREQ used (Total process time):

real time 0.07 seconds

cpu time 0.07 seconds

132

133 OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK;

145

Re: Counting unique observations in two datasets (merged by id)

Patrick — Wed, 19 Feb 2020 08:00:11 GMT

You can make it unique again using below code.

proc sort data=mg24(keep=id lung) out=unique_id_lung nodupkey;
  by id lung;
run;

title "Table 2: Lung frequencies in merged file d2,d4";
proc freq data=unique_id_lung;
  tables lung;
run;
title;

Not all rows from table D2 match with a row from table D4 so don't expect to get the same count.

With your sample data the row in D2 with ID OSa31 doesn't match with table D4 (there is no such ID in the data).

topic Counting unique observations in two datasets (merged by id) in SAS Studio

Counting unique observations in two datasets (merged by id)

Re: Counting unique observations in two datasets (merged by id)