May 27, 2021 SAS
Dear reader, the
following
are questions about SAS usage and design, and you may encounter the following problems during your usual programming operations.
Through the experience feedback of the vast number of users, the following frequently asked questions have been answered accordingly
More questions welcome the feedback of the vast number of users, we will continue to further answer.
The DO WHILE expression is evaluated at the top of the DO loop. I f the expression is evaluated for the first time, the DO loop is never executed. T HE DO UNTIL is executed at least once.
Characters, numbers
By using the MAXDEC option
The difference between the two procedures is that PROC MEANS generates reports by default. Instead, to generate a report in PROC SUMMARY, you must include a PRINT option in the PROC SUMMARY statement.
How do I specify the variables to be handled by the FREQ procedure?
By using the CABLES statement.
What is the purpose of two-tailed in the input statement?
The double-tailed tag indicates that SAS instead of advancing to the new record, saving the current input record to execute the next INPUT statement.
Use DROP, KEEP statements, and dataset options.
It produces default statistics for MIN, MAX, MEAN, and STD DEV.
PDV is the logical area in memory. C reate an input buffer after the PDV is created. SAS builds datasets in the PDV region of memory
It can also be used to write output without creating a dataset.
By using PROC SORT with NODUPKEY and NODUP options.
The NODUPKEY option removes duplicate observations, which repeat the values of variables listed in the BY statement, while the NODUP option removes duplicate observations where values in all variables are repeated (same observations)
Use the DESCENDING keyword in PROC SORT code.
Create variables with different names by using the PUT function.
Create variables with different names by using the INPUT function.
SET connects the dataset, where MERGE matches the observations of the dataset
SYMPUT places the values in the dataset into the macro variable, and SYMGET gets the values from the macro variables to the dataset.
The INTNX function advances a date, time, or date time value at a given interval and returns a date, time, or date time value
The RETAIN statement tells SAS not to set the variable to missing when it doesn't iterate from the current iteration of the DATA step to the next step. I nstead, SAS retains these values.
%EVAL cannot perform arithmetic calculations using the number of operations with floating-point values. I t is when the %SYSEVALF function appears.
It performs simple and multiple regression, variance analysis (ANOVAL), covariance analysis, multivariable variance analysis, and repeated measurement variance analysis.
SAS INFORMATS is used to read or enter data from an external file called a flat file ASCII file, text file, or sequential file. T he information tells the SAS how to read the data into the SAS variable.
Scan (parameter, n, separator)
Scan, Substr, Trim, Catx, Index, tranwrd, Find, Sum.
The TRANWRD function replaces or removes all character patterns that appear in the string.
InFILE statements are used to identify external files, while INPUT statements are used to describe variables.
When the MISSOVER option is used on an INFILE statement, the INPUT statement does not jump to the next line when reading a short line. Instead, MISSOVER sets the variable to missing
Declare using FIRSTOBS and OBS.
The SUM function returns the sum of the non-missing arguments, while the "plus" operator returns the missing value when any arguments are missing.
The SUBSTR function is used to extract substrings from character variables.
The ceil function returns the minimum integer greater than/equal to the argument, while the floor returns the maximum integer that is less than/equal to the argument.
SCAN extracts words within a value marked by a bounder. S UBSTR extracts a portion of the value by describing a specific location. W hen we know the exact location of the substring extracted from the character value, it is best to use it.
Use PROC SQL and COUNT (distinct variable_name) to determine the number of unique values for columns.
There are indications that some system options can be used to debug SAS macros: MPRINT, MLOGIC, SYMBOLGEN
Use PROC PRINTTO
The data step MERGE does not create a Descartes product in the case of a many-to-many relationship. P roc SQL generates the Descartes product.
2 bytes and 1 byte.
Programs are sub-routines with specific purposes, and data steps are designed to read in and manipulate data.
PUT (formatted) statement.
Where statement
Input functions - character-to-number conversion - Input (source, information) and put functions - number-to-character conversion input (source, format)
No, it must be a character data type.
The number of observations is limited only by the ability of computers to process and store them.
By using the MAXDEC option
BY processing requires that your data be sorted or indexed in the order of BY variables.
By using the CABLES statement.
Five
proc means giving an explanation statistic. B y default, it gives the output in the output window. B ut the proc summary does not give the output for default.we need to give an option to print, and then only it will give the output.
Use the Debug clause after the "/" in the data statement.
Use the MISSOVER keyword.