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feat: mp_prevobs.sas macro

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Allan Bowe
2020-12-23 00:33:59 +00:00
parent b3a8b4323e
commit 4c333ae7b3
2 changed files with 233 additions and 0 deletions
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145
all.sas
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@@ -4066,6 +4066,93 @@ select distinct lowcase(memname)
,dttm=%sysfunc(datetime()); ,dttm=%sysfunc(datetime());
quit; quit;
%mend;/**
@file
@brief Enables previous observations to be re-instated
@details Remembers the last X observations by storing them in a hash table.
Is a convenience over the use of lag() or retain, when an entire observation
needs to be restored.
This macro will also restore automatic variables (such as _n_ and _error_).
Example Usage:
data example;
set sashelp.class;
calc_var=_n_*3;
* initialise hash and save from PDV ;
%mp_prevobs(INIT,history=2)
if _n_ =10 then do;
* fetch previous but 1 record;
%mp_prevobs(FETCH,-2)
put _n_= name= age= calc_var=;
* fetch previous record;
%mp_prevobs(FETCH,-1)
put _n_= name= age= calc_var=;
* reinstate current record ;
%mp_prevobs(FETCH,0)
put _n_= name= age= calc_var=;
end;
run;
Result:
<img src="https://imgur.com/PSjHoET.png" alt="mp_prevobs sas" width="400"/>
Credit is made to `data _null_` for authoring this very helpful paper:
https://www.lexjansen.com/pharmasug/2008/cc/CC08.pdf
@param action Either FETCH a current or previous record, or INITialise.
@param record The relative (to current) position of the previous observation
to return.
@param history= The number of records to retain in the hash table. Default=5
@param prefix= the prefix to give to the variables used to store the hash name
and index. Default=mp_prevobs
@version 9.2
@author Allan Bowe
**/
%macro mp_prevobs(action,record,history=5,prefix=mp_prevobs
)/*/STORE SOURCE*/;
%let action=%upcase(&action);
%let prefix=%upcase(&prefix);
%let record=%eval((&record+0) * -1);
%if &action=INIT %then %do;
if _n_ eq 1 then do;
attrib &prefix._VAR length=$64;
dcl hash &prefix._HASH(ordered:'Y');
&prefix._KEY=0;
&prefix._HASH.defineKey("&prefix._KEY");
do while(1);
call vnext(&prefix._VAR);
if &prefix._VAR='' then leave;
if &prefix._VAR eq "&prefix._VAR" then continue;
else if &prefix._VAR eq "&prefix._KEY" then continue;
&prefix._HASH.defineData(&prefix._VAR);
end;
&prefix._HASH.defineDone();
end;
/* this part has to happen before FETCHing */
&prefix._KEY+1;
&prefix._rc=&prefix._HASH.add();
if &prefix._rc then putlog 'adding' &prefix._rc=;
%if &history>0 %then %do;
if &prefix._key>&history+1 then
&prefix._HASH.remove(key: &prefix._KEY - &history - 1);
if &prefix._rc then putlog 'removing' &prefix._rc=;
%end;
%end;
%else %if &action=FETCH %then %do;
if &record > &prefix._key then putlog "Not enough records in &Prefix._hash yet";
else &prefix._rc=&prefix._HASH.find(key: &prefix._KEY - &record);
if &prefix._rc then putlog &prefix._rc= " when fetching " &prefix._KEY=
"with record &record and " _n_=;
%end;
%mend;/** %mend;/**
@file @file
@brief Returns all children from a hierarchy table for a specified parent @brief Returns all children from a hierarchy table for a specified parent
@@ -4667,6 +4754,64 @@ proc sql
%mp_binarycopy(inloc="&inloc",outref=_webout) %mp_binarycopy(inloc="&inloc",outref=_webout)
%end; %end;
%mend;/**
@file mp_testwritespeedlibrary.sas
@brief Tests the write speed of a new table in a SAS library
@details Will create a new table of a certain size in an
existing SAS library. The table will have one column,
and will be subsequently deleted.
%mp_testwritespeedlibrary(
lib=work
,size=0.5
,outds=work.results
)
@param lib= (WORK) The library in which to create the table
@param size= (0.1) The size in GB of the table to create
@param outds= (WORK.RESULTS) The output dataset to be created.
<h4> Dependencies </h4>
@li mf_getuniquename.sas
@li mf_existds.sas
@version 9.4
@author Allan Bowe
**/
%macro mp_testwritespeedlibrary(lib=WORK
,outds=work.results
,size=0.1
)/*/STORE SOURCE*/;
%local ds start;
/* find an unused, unique name for the new table */
%let ds=%mf_getuniquename();
%do %until(%mf_existds(&lib..&ds)=0);
%let ds=%mf_getuniquename();
%end;
%let start=%sysfunc(datetime());
data &lib..&ds(compress=no keep=x);
header=128*1024;
size=(1073741824/8 * &size) - header;
do x=1 to size;
output;
end;
run;
proc sql;
drop table &lib..&ds;
data &outds;
lib="&lib";
start_dttm=put(&start,datetime19.);
end_dttm=put(datetime(),datetime19.);
duration_seconds=end_dttm-start_dttm;
run;
%mend;/** %mend;/**
@file @file
@brief Recursively scans a directory tree to get all subfolders and content @brief Recursively scans a directory tree to get all subfolders and content

88
base/mp_prevobs.sas Normal file
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@@ -0,0 +1,88 @@
/**
@file
@brief Enables previous observations to be re-instated
@details Remembers the last X observations by storing them in a hash table.
Is a convenience over the use of lag() or retain, when an entire observation
needs to be restored.
This macro will also restore automatic variables (such as _n_ and _error_).
Example Usage:
data example;
set sashelp.class;
calc_var=_n_*3;
* initialise hash and save from PDV ;
%mp_prevobs(INIT,history=2)
if _n_ =10 then do;
* fetch previous but 1 record;
%mp_prevobs(FETCH,-2)
put _n_= name= age= calc_var=;
* fetch previous record;
%mp_prevobs(FETCH,-1)
put _n_= name= age= calc_var=;
* reinstate current record ;
%mp_prevobs(FETCH,0)
put _n_= name= age= calc_var=;
end;
run;
Result:
<img src="https://imgur.com/PSjHoET.png" alt="mp_prevobs sas" width="400"/>
Credit is made to `data _null_` for authoring this very helpful paper:
https://www.lexjansen.com/pharmasug/2008/cc/CC08.pdf
@param action Either FETCH a current or previous record, or INITialise.
@param record The relative (to current) position of the previous observation
to return.
@param history= The number of records to retain in the hash table. Default=5
@param prefix= the prefix to give to the variables used to store the hash name
and index. Default=mp_prevobs
@version 9.2
@author Allan Bowe
**/
%macro mp_prevobs(action,record,history=5,prefix=mp_prevobs
)/*/STORE SOURCE*/;
%let action=%upcase(&action);
%let prefix=%upcase(&prefix);
%let record=%eval((&record+0) * -1);
%if &action=INIT %then %do;
if _n_ eq 1 then do;
attrib &prefix._VAR length=$64;
dcl hash &prefix._HASH(ordered:'Y');
&prefix._KEY=0;
&prefix._HASH.defineKey("&prefix._KEY");
do while(1);
call vnext(&prefix._VAR);
if &prefix._VAR='' then leave;
if &prefix._VAR eq "&prefix._VAR" then continue;
else if &prefix._VAR eq "&prefix._KEY" then continue;
&prefix._HASH.defineData(&prefix._VAR);
end;
&prefix._HASH.defineDone();
end;
/* this part has to happen before FETCHing */
&prefix._KEY+1;
&prefix._rc=&prefix._HASH.add();
if &prefix._rc then putlog 'adding' &prefix._rc=;
%if &history>0 %then %do;
if &prefix._key>&history+1 then
&prefix._HASH.remove(key: &prefix._KEY - &history - 1);
if &prefix._rc then putlog 'removing' &prefix._rc=;
%end;
%end;
%else %if &action=FETCH %then %do;
if &record > &prefix._key then putlog "Not enough records in &Prefix._hash yet";
else &prefix._rc=&prefix._HASH.find(key: &prefix._KEY - &record);
if &prefix._rc then putlog &prefix._rc= " when fetching " &prefix._KEY=
"with record &record and " _n_=;
%end;
%mend;