First last in sas

variable = 1 indicates an observation is the last observation in a BY group; Although FIRST.variable and LAST.variable temporary variables are not automatically written to a SAS data set, once identified they can be used for special processing, reporting purposes, the creation of new variables, modification of existing variables, the structural ...

First last in sas. If the first Def_type of the account is called 'Loss', then I'll pick the value of that date (ex. $3500 for account 1001) regardless what status the later dates have. However if the first value of the account is called 'Fee', then I'll pick the last value (ex. $40 for account 1003) regardless what status the later dates have.

Special Functions and CALL Routines: Matrix CALL Routines. Special Functions and CALL Routines: C Helper Functions and CALL Routines. Special Functions and CALL Routines: Other Functions. Functions for Calling SAS Code from Within Functions. The FCmp Function Editor. Examples: FCMP Procedure. The FONTREG Procedure.

Mike Sadler, who has died aged 103, was a former MI6 officer and an honorary member of "the Originals", as men of L Detachment of the early SAS are known. He was believed to be the last survivor of the Long Range Desert Group or LRDG, without which the fledgling SAS might not have thrived. He also has a piece of the Antarctic named after him.Since SAS processes row by row, we create a counter to count the number of observations per group. If SAS processes the first row of a new group, the counter is set to one again. We create the counter with the RETAIN statement. The RETAIN statement “remembers” the last value of the counter when SAS starts processing a new row.Apr 18, 2022 · Firstwk = First.wk; Lastwk = Last.wk; Firstpo = First.PO; Lastpo = Last.PO; run; Values of 1 for True and 0 for False. If you want a more interesting TOTAL that provide different numbers of records and/or additional variables to total, maybe named CS ZNL and LB and use ZNL_TOT = ZNL; 1 Like. Reply. The SQL language as originally defined in the 1980's and codified into 1992 standard that PROC SQL supports has no concept of first and last. Other implementations of SQL added extra non-standard features to get around this and ultimately the SQL standard was expanded to at least include windowing functions that allow something like processing ...Gumtree SA is a popular online marketplace where individuals can buy and sell items. With its wide reach and user-friendly interface, it has become a go-to platform for many South ...You can have numerous by variables, and for each one first and last automatic variables are generated. In this case first.social_security_number would return only one record per social_security_number. First.year is updated every time there is a change in the preceding by variable (s) as well as when there is a change in year. …Hi 🙂. I want to create a conditional variable (outcome) based on accident_id and road_user_type: - if anyone in an accident was a vulnerable road user > then outcome = 1; - else if everyone in an accident was a MVO > then outcome = 2; - else outcome = 3. Please help 🙂. dataset have;

documentation.sas.comThese keywords identify the first and last record in the grouping variable indicated after the BY statement. When an employee ID is unique, the first and last record will be the same row. Thus our code outputs employee ID's where the first and last records are not the same, to a dataset called "dupes", and all the other unique records are ...When reading with a wild card the files are treated as one stream. There is an option EOV to detect the start of a new file. You could test that variable and use programming logic to skip the first line of the file. You CAN use FIRSTOBS when reading the files with the FILEVAR option.CATT(item1, item2 <, item3, item4, …, item n>). CATS(item1, item2 <, item3, item4, …, item n>). The items 1 to n are the strings you want to concatenate. The CATX function has an extra, obligatory argument, namely a separator argument. With this argument, you can separate the input items in the output string.The value of these variables is either 0 or 1. SAS sets the value of FIRST. variable to 1 when it reads the first observation in a BY group, and sets the value of LAST. variable to 1 when it reads the last observation in a BY group. These temporary variables are available for DATA step programming but are not added to the output data set.

How SAS Determines FIRST. variable and LAST. variable. Example 1: Grouping Observations by State, City, and ZIP Code. Example 2: Grouping Observations by City, State, and ZIP Code. Example 3: A Change Affecting the FIRST. variable. How the DATA Step Identifies BY Groups. In the. DATA step. , SAS identifies the beginning and end of each. BY group.You can use the following methods to quickly concatenate strings in SAS. Method 1: Concatenate Strings with Space in Between. Method 2: Concatenate Strings with No Space in Between. Method 3: Concatenate Strings with Custom Delimiter. The following examples show how to use each method with the following dataset in SAS:You can have numerous by variables, and for each one first and last automatic variables are generated. In this case first.social_security_number would return only one record per social_security_number. First.year is updated every time there is a change in the preceding by variable (s) as well as when there is a change in year. …What is FIRST. & LAST. ? The SET and BY statements in a data step tell SAS to process the data by grouping observations together. Whenever we use BY statement with a SET statement, SAS automatically creates two temporary variables for each variable name that appears in the BY statement.If you came from a SAS programming background, you may have seen the INTNX function that applies basic arithmetic to dates. For example, you can use the function to add or subtract days, weeks, months, quarters, or years to an existing date. By setting the alignment parameter, you can establish if the resulting date will be in the beginning of the …

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Re: Finding first (or last) record using SQL. You could use the SQL to do ORDER BY before using the data step for First or Last processing. Solved: I typically use first. and last. in data step to select the first (or last) recordd within an ID. It is straightorward in SAS data step but.First and Last Variables. Using this code, I have understood that automatic variables FIRST.SubjID and LAST.SubjID are supposed to appear in the PDV. I am supposed to fill out the variables for FIRST.SubjID and LAST.SubjID, but am confused as to how to actually display these variables. data WORK.AEs; infile datalines; input SubjID.While Andreas already answered your question, I thought you might find it equally useful to know that the reason that you don't have to include Total_Amount_Last_Learning in a retain statement is because it is automatically retained because you used in the statement TOTAL_AMOUNT_LAST_EARNING + AMOUNT_LAST_EARNING ; . The variable on the left in such sum statements are automatically retained.The DATA step consists of a group of SAS statements that begins with a DATA statement. The DATA statement begins the process of building a SAS data set and names the data set. ... As the following figure illustrates, the INPUT statement causes SAS to read the first record of raw data into the input buffer. Then, according to the instructions in ...Major Mike Sadler, the last surviving member of the famous wartime squad known as L Detachment SAS, has died at the age of 103.The legendary squad nicknamed themselves 'The Originals', with Mike ...Hi, I want to get all the observations where first name starts with Ro, Ay, Su OR Last name starts with Che, Ro. I know it's possible to code with Where, IF etc, but can someone help with the coding with Perl, please. Thanks. data have; infile datalines; input id First_name$8. Last_name&$8.; da...

I would like to find the first and second earliest date per group. I'm used to doing this in the SQL SELECT statement, for example in Oracle using the NTH_VALUE function. I am unaware of a similar function in SAS proc SQL. The SAS RANK proc may work but I cannot get the values outputted as I want them. Example data:SUBSTR() function only works with the character variable. In order to extract last N digits you need to first convert numeric variable into char variable using PUT() function before passing it to substr function. Here is the classic example of how to extract last 4 digits from a numeric variable in SAS.You're most likely needing to use RETAIN (implicit or explicit) and FIRST/LAST processing. proc sort data=sashelp.class out=class; by sex; data want; set class; *by group specified; by sex; *keep across rows; retain max_age; *if first of each Sex group; if first.sex then max_age = age; *other records; else max_age = max(age, max_age); *if last ...For posterity, here is how you could do it with only a data step: In order to use first. and last., you need to use a by clause, which requires sorting: proc sort data=BU; by ID DESCENDING count; run; When using a SET statement BY ID, first.ID will be equal to 1 (TRUE) on the first instance of a given ID, 0 (FALSE) for all other records.SAS does not write FIRST. and LAST. variables to the output data set, so you cannot display their values with the PRINT procedure. Therefore, the simplest method of displaying the values of FIRST. and LAST. variables is to assign their values to other variables. This example assigns the value of FIRST.TOURTYPE to a variable named FirstTour and ...Re: Finding first (or last) record using SQL. You could use the SQL to do ORDER BY before using the data step for First or Last processing. Solved: I typically use first. and last. in data step to select the first (or last) recordd within an ID. It is straightorward in SAS data step but.data uscpi_dedupedByYear; set uscpi_sorted; by year; if first.year; /*only keep the first occurence of each distinct year. */. /*if last.year; */ /*only keep the last occurence of each distinct year*/. run; A lot depends on who your input dataset is sorted. For ex: If your input dataset is sorted by year & month and you use if first.year; then ...If you use a by statement along with a set statement in a data step then SAS creates two automatic variables, FIRST.variable and LAST.variable, where variable is the name of the by variable. FIRST.variable has a value 1 for the first observation in the by group and 0 for all other observations in the by group.Finding duplicates is simple with SAS "FIRST." and "LAST." expressions. Find duplicates save resources, ie, money, that can be used for other tasks. Using the FIRST. And LAST. expressions is a quick and easy way to find duplicated data. Using SAS expressions can save a lot of coding time. Author Clarence Wm. Jackson, CSQAWhile Andreas already answered your question, I thought you might find it equally useful to know that the reason that you don't have to include Total_Amount_Last_Learning in a retain statement is because it is automatically retained because you used in the statement TOTAL_AMOUNT_LAST_EARNING + AMOUNT_LAST_EARNING ; . The variable on the left in such sum statements are automatically retained.3. PROC APPEND To Concatenate Datasets. This is a very popular SAS procedure when it comes to appending the two datasets. The only drawback with this method is, it can only appends two datasets at a time.Whereas first methods can combine and append two or more dataset at the same time.. You could append more than two datasets using the proc append method but you have to write this procedure ...With SAS OnDemand for Academics, you get the same world-class analytics software used by more than 82,000 business, government and university sites around the world - including 100% of Fortune 500 companies in commercial and retail banking, health insurance, pharmaceuticals, aerospace manufacturing, e-commerce and computer services. ...

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Jan 29, 2015 · The Right Way to Obtain Duplicates in SAS. To obtain ALL duplicates of a data set, you can take advantage of first.variable and last.variable . Here is the code to do it with the above example data set of test; you will get both the single observations and the duplicate observations. Nov 2, 2023 · The FIRST. And LAST. functions can be used to identify first or last observations by group in the SAS dataset. First.Variable : It assigns value 1 to the first observation and 0 to the rest of the observations within the group in a SAS dataset. Then when the code executes, SAS creates temporary numeric variables first.var1, last.var1; first.var2, last.var2. These variables have 0/1 values for false/true, and indicate if the current row is the first or last row being input into a DATA or PROC step from the BY-group defined by the specified variable. The relevant 9.4 documentation is at:The easiest way to remove the first character from a string in SAS is to use the SUBSTR function.. You can use the following basic syntax to do so: data new_data; set original_data; string_var = substr (string_var, 2); run; . This syntax extracts the substring starting from the second character to the end of the string, which has the effect of removing the first character from the string.Sep 11, 2019 · If you want to do so with PROC SQL, this has nothing to do with first./last. logic, which is a SAS Data Step concept. proc sql; create table want as. select * from sam. group by name. having value=min(value); quit; Result: name item value. naari battary 14. nehemiah ball 20. Jul 10, 2019 · SAS Version 9.4 Good day and thank you for looking at my question. data work.have; infile datalines dlm=' '; input CN $1. @5 SEN $1. @9 RT $1. @12 Value; datalines; x p d 5 x p b 7 x u d 6 x u b 8 y t d 2 y t b 8 z t d 3 z t b 9 q p d 4 q p b 6 ; run; proc sort data=work.have; by cn sen; run; T... SAS does not write FIRST. and LAST. variables to the output data set, so you cannot display their values with the PRINT procedure. Therefore, the simplest method of displaying the values of FIRST. and LAST. variables is to assign their values to other variables. This example assigns the value of FIRST.TOURTYPE to a variable named FirstTour and ...

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If you came from a SAS programming background, you may have seen the INTNX function that applies basic arithmetic to dates. For example, you can use the function to add or subtract days, weeks, months, quarters, or years to an existing date. By setting the alignment parameter, you can establish if the resulting date will be in the beginning of the period, at the end, middle, or the same as the ...I wrote some code to count the number of prescriptions and had originally restricted later analyses to RX = 1, but as we can see, that doesn't work for people with multiple scripts on the same encounter (Patient 2222). data pt_meds_; set pt_meds; by patient_num; if first.patient_num then RX = 1; else RX + 1;The DO statement, the simplest form of DO-group processing, designates a group of statements to be executed as a unit, usually as a part of IF-THEN/ELSE statements. The iterative DO statement executes statements between DO and END statements repetitively based on the value of an index variable. The DO WHILE statement executes statements in a DO ...INDEX v/s INDEXC v/s INDEXW in SAS. INDEX - It searches a specified substring and returns the position of its first occurrence from the character string.; INDEXC - It searches characters from a specified substring and returns the position of the first occurrence of any character from a given substring.; INDEXW - It searches for the exact character, word, or substring mentioned in the ...While you may have obscure problems with names like Vincent Van Gogh, your basic idea for first and last name are correct. You can check whether there are 3 names, and only assign the middle name if there is one. The DATA step syntax is easy: if countw (fullname) > 2 then second = scan (fullname, 2, ' '); The SQL syntax is harder, and just a ...Inkatha had been boycotting the process and challenging the ANC in violent street protests. The peaceful election brought enormous relief to the country and the world. A Kenyan, Washington Okumu, alternately described as a professor or a diplomat, was credited with the negotiation. But few observers knew who he was.Example 3: Select First and Last Observations In SAS Using END=Option. You can extract first and last observations from a SAS dataset using _N_ automatic variable and END=last_obs option. First observation can be selected using _N_; Last observation can be selected using end= option; The following code shows how to select first and last ...Mar 8, 2018 · And, Why for the first set are you missing the first entry? subs1 = "JDE1, LEI0" -> where's the first one? So you're trying to create subsets for each tech group based on the subtech groups? You can add a WHERE to the select statement, but I don't understand why you don't just join them and find the values you need. or use an approach like this. I need to find out customers with different names and same address. I tried this code, but got note as follows. data rawdata2; set rawdata1; /* (my .csv which has name, address and zip)*/. if first.name and last.Address and last.zip_code; run; NOTE: Variable 'first.name'n is uninitialized. NOTE: Variable 'last.Address'n is uninitialized.Query Builder uses SQL which doesn't have the concept of FIRST/LAST. Since it seems like all it does is create summary statistics you should be able to replace it with a Summary Task though. @reminder65 wrote: Hello, I am a SAS learner, trying to find a way to break down a hand-written code into series of query builders for more user friendly ...Re: How to get the first day of a week. The SAS calendar function intnx () will allow you to shift a week to wherever you want to. BUT: You need a SAS date value as starting point for this. intnx ('week',<sas date value>,0,'b') would give you the Sunday the week starts, intnx ('week.2',<sas date value',0,'b') would give you the Monday. ….

The sample code on the Full Code tab takes a SAS date variable and finds the first business day of that month. It uses the INTNX function to advance to the first day of the month. Then it uses the WEEKDAY function to determine the day of the week. If the first day is a Saturday or Sunday, then it advances the FIRST variable by 2 or 1, respectively.At the very first observation of each group (identified by the internal variable first.date, which takes the value 1 in this case), seq_id is set to 1. For all the next observations of the same date, the condition 'if first.date' is false so SAS applies the 'else' statement, which results in the accumulation of seq_id's previous value + 1 -> so ...Go to Tasks>Describe. Try a few of the procedures to see what they give you. You're probably looking for a table analysis or a one way freq. If you really only want the first record of a data set then look at TASKS>DATA>SORT. Under the options for the Sort procedure you can keep just the first of each sorted field.Discrete categories in SAS are (by default) arranged in alphabetical order, so I use the values 1, 2, 3, and 4 to encode the RECIST values and I create a user-defined format to display those values as text. ... The new waterfall plot (click to enlarge) has axis labels that indicate the first and last patients; intermediate patient numbers ...Re: first.* is unitialized. In order to use first. syntax, you must use a BY statement in your data step: BY code; The =1 is unnecessary, it is implied TRUE. And I don't believe you can use FIRST. together with WHERE (since WHERE does not aware of what is going on in the data step, IF is). /Linus.Hi 🙂. I want to create a conditional variable (outcome) based on accident_id and road_user_type: - if anyone in an accident was a vulnerable road user > then outcome = 1; - else if everyone in an accident was a MVO > then outcome = 2; - else outcome = 3. Please help 🙂. dataset have;You can use the FIRST. and LAST. functions in SAS to identify the first and last observations by group in a SAS dataset. Here is what each function does in a nutshell: FIRST.variable_name assigns a value of 1 to the first observation in a group and a value of 0 to every other observation in the group.Hi, Thank you for your message, this code was just an example. I would like to check for thsi text: text text text text end of line of this text some other text and here we are if the text 'some other text' is the last text at the end of the last row I want to assign a value to a variable, else if there is text 'and here we are' then i want to assign another value to the variable ( without ... First last in sas, Re: If first. then group by; how to restart count. You have to include the variables in the BY statement if you want SAS to set values for FIRST. and LAST. variables for them. You have to tell SAS not to reset the new variable COUNT to missing when it starts the next iteration., 1:36. The US services sector unexpectedly contracted in April for the first time since 2022 as a gauge of business activity slumped to a four-year low and a measure of …, Re: Keep only first/last observation for EACH year of EACH company. Posted 01-29-2019 10:06 PM (1071 views) | In reply to shafayat. 1) Create a year variable. 2) Sort by permno and year. 3) then, in a data step do. data newData; set myData; by permno year; if first.year or last.year; run;, To accomplish, he sorted the data on multiple columns with case_id as the first criteria. Then he sorted the data again with proc sort nodupkey by case_id to return the top record for each case_id. If his original sorting criteria is correct, he will return the most impacting sub-action for each case_id., 6. I have recently migrated to Python as my primary tool for analysis and I am looking to be able to replicate the first. & last. functionality found in SAS. The SAS code would be as follows; data data.out; set data.in; if first.ID then flag = 1; if last.ID then flag = 1; run; The output would be as follows;, The TRANWRD function replaces all occurrences of a given substring within a character string. The TRANWRD function does not remove trailing blanks in the target string and the replacement string. Comparisons. The TRANWRD function differs from the TRANSTRN function because TRANSTRN allows the replacement string to have a length of zero., What is FIRST. & LAST. ? The SET and BY statements in a data step tell SAS to process the data by grouping observations together. Whenever we use BY statement with a SET statement, SAS automatically creates two temporary variables for each variable name that appears in the BY statement., Re: How to get the first day of a week. The SAS calendar function intnx () will allow you to shift a week to wherever you want to. BUT: You need a SAS date value as starting point for this. intnx ('week',<sas date value>,0,'b') would give you the Sunday the week starts, intnx ('week.2',<sas date value',0,'b') would give you the Monday., 2. You want to SORT the data by SUBJECT and NO. But tell the DATA step to group it by SUBJECT and AVAL. You will need the NOTSORTED keyword because it is not sorted by AVAL value. set test; by SUBJID AVAL notsorted; if first.AVAL then FLG = 1; if last.AVAL then FLG = 2; PS The FIRST. and LAST. flag variables are not functions., What is FIRST. & LAST. ? The SET and BY statements in a data step tell SAS to process the data by grouping observations together. Whenever we use BY …, Hi, I have a dataset in which Obs can become either "1" or "0". For every observation where Obs is "0", it needs to be determined the time when Obs started to be "0" (Time_first), the next time it becomes "1" (Time_last), and the time of the next observation (Time_next). The best solution I found ..., 1002 30-09-21 Q3. 1002 31-12-21 Q4. I want to remove the duplicates and keep only the last entry based on the variable "Quarter" for a given firm. I want two resulting datasets. The first is a clean dataset as follows: GVKey Report_Date Quarter. 1001 31-03-21 Q1. 1001 30-06-21 Q2. 1001 10-10-21 Q3., You can use the SCAN function in SAS to extract the nth word from a string. This function uses the following basic syntax: SCAN (string, count) where: string: The string to analyze. count: The nth word to extract. Here are the three most common ways to use this function: Method 1: Extract nth Word from String. data new_data;, Hi, I have a dataset in which Obs can become either "1" or "0". For every observation where Obs is "0", it needs to be determined the time when Obs started to be "0" (Time_first), the next time it becomes "1" (Time_last), and the time of the next observation (Time_next). The best solution I found ..., Re: COUNTER, RETAIN AND FIRST. The very first thing you will need to explain is the sort order. Since to use FIRST. there must be a BY statement, then please at least share the BY statement you are using. Solved: Hello, I'm a 2 month old SAS user and just started practicing COUNTER, RETAIN, FIRST. ,Last. and DO/END., I need to find out customers with different names and same address. I tried this code, but got note as follows. data rawdata2; set rawdata1; /* (my .csv which has name, address and zip)*/. if first.name and last.Address and last.zip_code; run; NOTE: Variable 'first.name'n is uninitialized. NOTE: Variable 'last.Address'n is uninitialized., We can use the following LAST. function in SAS to assign a value of 1 to the first observation for each team in the dataset: /*sort dataset by team*/ proc sort data =my_data; by team; run; /*create new dataset that labels last row for each team*/ data last_team; set my_data; by team; last_team=last.team; run; /*view dataset*/ proc print data ..., ECSTDTC and LAST.ECENDTC could only be true if there is only one record for that value of ECSTDTC within that value of USUBJID. If your data it properly sorted and has no missing values then you want. data ec1; set ec7; by usubjid ; retain first_start ; if first.usubjid then first_start=ECSTDTC; if last.usubjid ;, Hi @SasStatistics, You can also use the POINT= option of the SET statement to take one step back in the sequence of observations. The CUROBS= option helps to determine the appropriate observation number. data want; set have curobs=_n; by id; if last.id & ~first.id then do; _p=_n-1; set have point=_p; output; end; run;, For example, the loop do i = 1 to 10 while (x < 20); x = i*4; output; end; will stop iterating when the value of x reaches or exceeds 20. DO UNTIL Loop: This loop continues to iterate until a certain condition is met. The condition is checked after each iteration. For example, the loop do i = 1 to 10 until (x > 30); x = i*4; output; end; will ..., On the one hand it sounds like you want to GENERATE data based on some macro variable. If that is the case write a date step. You should be able to write the data step using data step DO looping and just set the bounds of the loops using the macro variables. data want; do c= 1 to &num_clusters;, Hi all, I have to admit my do-loop skill is too weak. I need to sort out the first and last months when shipping was made for each year within a year. As shown below, the columns of startmon and endmon are my objective variables I want. OrderID mons mon1 mon2 mon3 mon4 mon5 mon6 mon7 mon8 mon9 mon1..., April 30, 2024 at 4:34 AM PDT. Listen. 1:32. A takeover of Anglo American Plc would need to be pitched at more than £30 ($37.6) per share, a higher price than BHP Group Ltd. offered last week ..., April 30, 2024 at 4:34 AM PDT. Listen. 1:32. A takeover of Anglo American Plc would need to be pitched at more than £30 ($37.6) per share, a higher price than BHP …, 4. Using Joe's example of a macro variable to specify the number of observations you want, here is another answer: do _i_=nobs-(&obswant-1) to nobs; set have point=_i_ nobs=nobs; output; end; stop; /* Needed to stop data step */. This should perform better since it only reads the specific observations you want., Re: How to Swap first and last record using Temporary Arrays. If you have more than 2 obs. in the dataset, this one works too: ; run; proc print; run; data want; do point=nobs,2 to nobs-1,1; set list point=point nobs=nobs; output; end; Bart., How to use the function "first" and "last" in SAS - Stack Overflow. Asked 1 year, 11 months ago. Modified 1 year, 11 months ago. Viewed 510 times. 0. I'd like to get the variable FLG using first and last function in SAS. The data is sorted by No. The following my program is wrong. How do I get it? Please give me some advice. data test;, Join us for SAS Innovate April 16-19 at the Aria in Las Vegas. Bring the team and save big with our group pricing for a limited time only. Pre-conference courses and tutorials are filling up fast and are always a sellout., As Paige said, the best tool is data step,NOT sql. Anyway, there is some sql code could get first last. But I don't like it. proc sort data=sashelp.class out=have;by sex;run; ods select none; ods output sql_results=sql_results; proc sql number; select * from have; quit; ods select all; proc sql; create table want as select * from sql_results group by sex having row=min(row) or row=max(row); quit;, The last line appears to be unnecessary at least for the sample data. I have modified the code as below. See if this is what you intended. data firstlast; input string $60.; First_Word=scan(string,1,"&"); Last_Word=scan(string, -1,"&"); datalines; Jack and Jill Bob & Carol & Ted & Alice & Leonardo Gates ; proc print data=firstlast; run;, Eventually, you will know enough about it so that you can anticipate and code around any of the problems. Typically the case you describe involves the use of a subsetting IF in combination with a BY statement. A subsetting IF can delete an observation having FIRST.xxx or LAST.yyy equal to 1., ECSTDTC and LAST.ECENDTC could only be true if there is only one record for that value of ECSTDTC within that value of USUBJID. If your data it properly sorted and has no missing values then you want. data ec1; set ec7; by usubjid ; retain first_start ; if first.usubjid then first_start=ECSTDTC; if last.usubjid ;, A DO loop in SAS can be used to do some action a certain number of times.. There are three basic DO loops in SAS: 1. DO Loop. data data1; x = 0; do i = 1 to 10; x = i*4; output; end; run;. What It Does: This loop performs 10 iterations, from i = 1 to 10, where the value in each row is equal to i multiplied by 4.. When It Stops: This loop only stops after 10 iterations have been performed.