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;