重复数据的相关问题

临床试验中通常会遇到这样的情况：一个病床号对应了不同的患者或者一个患者对应了不同的病床号。这种情况可以归类为重复数据问题。下面有几种方法来学习重复数据的检查与相关处理。

1.利用data步来实现

proc sort data=clean.patients out=tmp;

by Patno;

run;

data dup;

set tmp;

by Patno;

if first.Patno and last.Patno then delete;

run;

2.利用proc freq实现

proc freq data=clean.patients noprint;

tables Patno / out=dup_no(keep=Patno Count

where=(Count gt 1));

run;

proc sort data=clean.patients out=tmp;

by Patno;

run;

proc sort data=dup_no;

by Patno;

run;

data dup;

merge tmp dup_no(in=Yes_dup drop=Count);

by Patno;

if Yes_dup;

run;

3.利用proc sql语句处理

proc freq data=clean.patients noprint;

tables Patno / out=dup_no(keep=Patno Count

where=(Count gt 1));

run;

proc sql noprint;

select quote(Patno)

into :Dup_list separated by " "

from dup_no;

quit;

title "Duplicates selected using SQL and a macro variable";

proc print data=clean.patients;

where Patno in (&Dup_list);

run;

附

下面数据来源于《cody's data cleaning techniques using sas》一书

建立样本数据：

data clean.patients;

input @1 Patno $3. @4 gender $1.

@5 Visit mmddyy10.

@15 HR 3.

@18 SBP 3.

@21 DBP 3.

@24 Dx $3.

@27 AE $1.;

LABEL Patno = "Patient Number"

Gender = "Gender"

Visit = "Visit Date"

HR = "Heart Rate"

SBP = "Systolic Blood Pressure"

DBP = "Diastolic Blood Pressure"

Dx = "Diagnosis Code"

AE = "Adverse Event?";

format visit mmddyy10.;

datalines;

001M11/11/1998 88140 80 10

002F11/13/1998 84120 78 X0

003X10/21/1998 68190100 31

004F01/01/1999101200120 5A

XX5M05/07/1998 68120 80 10

006 06/15/1999 72102 68 61

007M08/32/1998 88148102 0

M11/11/1998 90190100 0

008F08/08/1998210 70

009M09/25/1999 86240180 41

010f10/19/1999 40120 10

011M13/13/1998 68300 20 41

012M10/12/98 60122 74 0

013208/23/1999 74108 64 1

014M02/02/1999 22130 90 1

002F11/13/1998 84120 78 X0

003M11/12/1999 58112 74 0

015F 82148 88 31

017F04/05/1999208 84 20

019M06/07/1999 58118 70 0

123M15/12/1999 60 10

321F 900400200 51

020F99/99/9999 10 20 8 0

022M10/10/1999 48114 82 21

023f12/31/1998 22 34 78 0

024F11/09/199876 120 80 10

025M01/01/1999 74102 68 51

027FNOTAVAIL NA 166106 70

028F03/28/1998 66150 90 30

029M05/15/1998 41

006F07/07/1999 82148 84 10

;

run;