Thanks a lot for reply, @Tom ! So this is what I understand now: (1) The if _n_=1 then do; statement is ALWAYS necessary in hash method, i.e., the basic syntax of hash method could be the follows (the scenario is I have two datasets, dsn1 and dsn2, I would like to combine them base on a key column, column1) , am I right or wrong? Another question is that, for the rc=h.find(key: column1); statement, I see there are examples such as rc=h.find(); , i.e., there is no key column specified inside the brackets, my question is: when do I need to specify the key:column in this statement? data combine; if _n_=1 then do; declare hash h(dataset: 'dsn1'); h.definekey('column1'); h.definedata('column2','column3'); h.definedone(); end; set dsn2; rc=h.find(key: column1); if rc=0; run; (2) The if 0 then set; is NOT always necessary, but in a lot of cases I need to write this statement. And it can be replaced by call missing (column1,column2,column3); statement after the h.definedone(); statement, am I right? (3) When writing hash codes and do NOT write if 0 then set; I sometimes get error message such as: (a) ERROR: Undeclared data symbol columnxxx for hash object, and (b) ERROR: Variable columnxxx has been defined as both character and numeric. Does this mean, always add the if 0 then set; statement in my hash code if I do not know whether I need to write it? ... View more

Hi this is the answer base on others' reply and codes: data class; input Name$ Sex$ Age Height Weight; datalines; Alfred M 14 69.0 112.5 Alice F 13 56.5 84.0 Barbara F 13 65.3 98.0 Carol F 14 62.8 102.5 Henry M 14 63.5 102.5 ; run; data cities; input zipcode City :$30. Department :$30. Persona:$10.; infile datalines dlm=',' dsd; datalines; 75008, Paris 8è ,Paris,Alice 91940, Les Ulis, Essonne,Carol 92330,Sceaux, Hauts-de-Seine,Henry 93140, Bondy , Seine-Saint-Denis,Henry 94150, Rungis, Val-de-Marne,Alice ; run; proc print data=class;run; proc print data=cities;run; data set1; if _n_=1 then do; if 0 then set class(keep=name sex age); declare hash match1(dataset:'class'); match1.definekey('name'); match1.definedata('sex','age'); match1.definedone(); end; set cities(keep=persona department); name=persona; rc=match1.find(key:name); if rc=0; drop persona rc; run; proc print data=set1;run;   ... View more

Hi Paige, thanks a lot for reply, so in most cases, split table is not necessary, unless one really need to do so. ... View more

Hi @PaigeMiller , thanks a lot for your comments!😀 Although I do not quiet understand what you mean😀 ... View more

Hi @ShelleySessoms , thanks a lot for your attention and taking care of this, 😀regards ... View more

Hi @Kurt_Bremser , thanks a lot for reply and your comments! Although I do not quiet understand what you said, I appreciate 😀! ... View more

Hi @Kurt_Bremser thanks a lot for your attention (and @ChrisHemedinger as well) and taking care of this, I appreciate 😀, thank you, regards and best😀   And @flag_hunter_202 , I do not know who you are, I did not want to be mean to you(also I do feel bad and sad to write such a tough and harsh post here in the community because such a post makes me look like a tough and harsh person but I am not), maybe you send that message without any bad intention, or maybe you do not write English and just want to send a message for fun or for joke, but I just got confused, annoyed by your meaningless private message, and I was nervous and intense, especially when I look at your account there was nothing, receiving a meaningless message from a meaningless account (and you know there is a person behind this account but you do not know who is this person and why this person behind the account pay attention to you) can be horrible/horrifying😠. So all this was the reason I posted your message and account. Hope you read my post and understand (if you do not read English you can use translation tools, but from your account name I can see that you know English, and the account name, what is flag hunter 202, what does it mean (and what is 202, is it a room number, it is very close to my room number I just noticed this somehow😠 are you kidding me), it makes things looks a bit more mysterious and scary, are you trying to scare me, or just for fun for joke, who are you😠 and now I somehow again noticed (see screen capture in my post) that you opened your account (member since 05-27-2025) is exactly one year later than mine (member since 05-27-2024 ), also you sent that meaningless message to me on 06-27-2025 exactly one month after you open your account, is all these dates coincidence or you meant to scare me? Why are you so mean?? Who are you? Do you know me or do I know you? Are you making fun or for fun or for joke, and you think this is fun and this would not scare/hurt others? why do you do this to others, it is so mean and scary) I hope you read my post and understand 😠 regards ... View more

Hi Tom, I think this thread (your 2nd thread) is the best answer for my post (solves major problems regarding the codings in my post and my thinking and question in mind). PaigeMiller replied me first and offered a very good solution and possible improvement for my answer (and also the loop within a statement is a technique I just need to learn) and I marked as the answer. ... View more

Hi @Tom , thanks for this further explain! So using sql to generate code for data step's character string is totally(or absolutely) unstable and unreliable approach. In any case when I can use data step, never try that approach. In simpler words, when I need to write data step's code, I just write data step, do not write other steps such as proc sql or marcos😀. ... View more

Hi @Tom , thanks for reply! The code in the screen capture consumes a lot of eyesight and also it was a bit too complex for me😀, so I did not run and test it while learning the material. I did not follow that solution (the code in the screen capture) in the material and wrote my own answer (the code in the text box) to that practice question.   I think you are right that, to resolve macro variable &allsteps, the %runSteps macro was not necessary, just use %put &allsteps; (or the %put is also unnecessary maybe) and one can solve it. And after reading your reply, I look at the code (in the screen capture) again, I can see that the code was intended to generate the code for a repeated data step through the proc sql step. Perhaps it is a technique worth learning , in case of some unusual and rare scenarios (I hope not😀) you just need to use sql to generate character strings for a data step. ... View more

I think you are right. I'll use this technique when need to split dataset. The syntax is a bit more complex comparing to mine (and I was not familiar with a loop within a statement and I once put extra semicolon and also put the semicolon in wrong place). Thanks a lot for reply me! ... View more

Hi @k26_23 , this is your data set A. I have not figure out the solution for your request, also I do not quiet understand the intention of your request, i.e., what kind of dataset you would like to create, and what's for?   It looks to me like you are working on a dataset that has link ID to other datasets. But what's the sort-order column for? Looking from your dataset A, this column is character (if it is numeric the '01' to '06' would be displayed like '1' to '6', without the leading 0), so what's this column for (I converted this column to numeric, incase it is needed as an order variable)?   And it looks to me like, by the sort-order column you created a number for each Parameter column value, if so why not just order your data according to the Parameter column? Are you prompting some convoluted question and a false request that confused yourself? I tried some sql step but did not get the dataset you request. I'll post it here also. data tumor1; input Subject $1-7 Site 9-11 ID $13-17 Description $32. Parameter $51-61 ParamDesc $43. sortorder $12.; sortordernum=input(sortorder,8.); datalines; 101-276 101 NTLDAT Date of Assessment 01 101-276 101 NTL01 CARCINOMATOSIS:CARCINOMATOSIS NTLSTAT Status 02 101-276 101 NTL02 LIVER:LIVER LESIONS NTLSTAT Statu 02 101-276 101 TLDAT Date of Assessment 03 101-276 101 TL01 ABDOMEN:RUQ OMENTAL MET TLMEAS_C Measurement 04 101-276 101 TL02 ABDOMEN:LEFT ABDOMEN OMENTAL MET TLMEAS_C Measurement 04 101-276 101 TL03 LIVER:LEFT LIVER DOME TLMEAS_C Measurement 04 101-276 101 TL04 LIVER:RIGHT LIVER DONE TLMEAS_C Measurement 04 101-276 101 TL01 ABDOMEN:RUQ OMENTAL MET TLYN1 Was lesion assessed at this visit 05 101-276 101 TL02 ABDOMEN:LEFT ABDOMEN OMENTAL MET TLYN1 Was lesion assessed at this visit 05 101-276 101 TL03 LIVER:LEFT LIVER DOME TLYN1 Was lesion assessed at this visit 05 101-276 101 TL04 LIVER:RIGHT LIVER DONE TLYN1 Was lesion assessed at this visit 05 101-276 101 TL01 ABDOMEN:RUQ OMENTAL MET TLYN2 Check if lesion is too small to measure 06 101-276 101 TL02 ABDOMEN:LEFT ABDOMEN OMENTAL MET TLYN2 Check if lesion is too small to measure 06 101-276 101 TL03 LIVER:LEFT LIVER DOME TLYN2 Check if lesion is too small to measure 06 101-276 101 TL04 LIVER:RIGHT LIVER DONE TLYN2 Check if lesion is too small to measure 06 101-276 101 TLSUM_C Sum of Diameters 07 101-276 101 NLDAT Date of Assessment 08 101-276 101 NL01 LIVER:RIGHT LOBE LIVER LESION NLSTAT Status 09 101-276 101 NL02 LIVER:LIVER LESIONS NLSTAT Status 09 101-276 101 NL01 LIVER:RIGHT LOBE LIVER LESION NLMEAS Measurement 10 101-276 101 NL02 LIVER:LIVER LESIONS NLMEAS Measurement 10 101-276 101 RSDAT Date of Assessment 11 101-276 101 RSORRES1 RECIST 1.1 Target Response 12 101-276 101 RSORRES2 RECIST 1.1 Non-Target Response 13 101-276 101 RSYN1 Were unequivocal new lesions identified 14 101-276 101 RSORRES4 Tumor Biomarker Response 15 101-276 101 TLPCNTCH % Change from Baseline 16 101-276 101 TLNADIR % Change from NADIR 17 101-276 101 RSORRES3 RECIST 1.1 Overall Response 18 ; run; proc print data=tumor1;run; The sql step I tried: (it does not create the request dataset though, just add a hint to solve the question): proc sql; select * from tumor1 group by sortordernum order by sortordernum,id; quit; ... View more