Data Step Programming

8/3/2019 Data Step Programming

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Technical Team


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SAS BasicsTraining


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Confidential & Proprietary Copyright 2010 The Nielsen Company 3AC BA HUB - Technical Team

Reading a SAS Data Set

To create a SAS data set using a SAS data set as input, you must use a

DATA statement to start a DATA step and name the SAS data set being

created

SET statement to identify the SAS data set being read .


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General form of a DATA step:

Concatenating SAS Data Sets

DATA output SAS-data-set;SET input data-set1 input data-set2 ;additional SAS statements ;

RUN;

The SET statement in a data step reads observations from one or more

data sets.

Any number of data sets can be in the SET statement

The observations from the first data set in the set statement appear first

in the new data set, the observations from the second data set follow

those from the first, and so on.


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Concatenating SAS Data Sets

Example-1

Data store3;

set sundari.Store2;

Run;

Note: This is just copy the observation from store2 data set.

Example-2

Data store3;

set sundari.Store2 sundari.store1;

Run;


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Drop and Keep Statements

The Drop Statement specifies the names of the variables to omit from the

output dataset (s)

Example:

Data store4;


drop state Top1_Brand Top2_brand Dollaramt;Run;

DROP variable(s);


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Drop and Keep Statements

The Keep Statement specifies the names of the variables to write to the

output dataset (s)

Example:

Data store5;


Keep Store_Id City Store_size Number_Items_Sold;

Run;

Keep variable(s);


8/24Confidential & Proprietary Copyright 2010 The Nielsen Company 8AC BA HUB - Technical Team

Drop and Keep Options

Alternatives to the DROP and KEEP statements are the DROP= and

KEEP= data-set options placed in the DATA statement:

Example:

Data store6 (Drop= state Top1_Brand Top2_brand Dollaramt);


Run;

DATA output-data-set (DROP = variable-list);




This options can also be placed in the SET statement to control which

variables are read from the input data set:

Example:

Data store7;

set sundari.Store2 sundari.store1(Drop= state Top1_Brand

Top2_brand Dollaramt) ;

Run;

Set input-data-set (DROP = variable-list);




Alternatives to the DROP and KEEP statements are the DROP= and

KEEP= data-set options placed in the DATA statement:

Example:

Data store6 (Keep=Store_Id City Store_size Number_Items_Sold);


Run;

DATA output-data-set (Keep = variable-list);




This options can also be placed in the SET statement to control which

variables are read from the input data set:

Example:

Data store7;

set sundari.Store2 sundari.store1(Keep=Store_Id City Store_size

Number_Items_Sold);

Run;

Set input-data-set (Keep = variable-list);



The Rename Data-Set Option

The RENAME = data set option changes the name of a variable.

General form of the RENAME= Data step option:

data-set (RENAME = (old-name1 = new-name1

old-name2 = new-name2...

old-name n = new-name n));



The Rename Data-Set Option

If the RENAME = option is associated with an input data-set in the SET

statement, the action applies to the data set that is being read.

Example:

Data store8;

set sundari.Store3 sundari.store4(rename=( City = CityName

Dollaramt = Amount)) ;

Run;



Interleaving SAS Data Sets

Use the SET statement with a BY statement in a DATA step to interleave

SAS data sets.

General form of a DATA step interleave:

Here data sets must be sorted first.

DATA output SAS-data-set;

SET input data-set1 input data-set2 ;

BY variables;

;

RUN;



Appending and Concatenating

Appending and Concatenating involves combining SAS data-sets

one after the other, into a single SAS data-set

Appending adds the observations in the second data set directly to

the end of the original data set.

Concatenating copies all the observations from the first data set and

then copies all observations from one or more successive data sets

into a new data set.



Appending

General form of the Append procedure:

BASE = names the data-set to which the observations are added.

DATA = names the data-set containing observations that are added to

the base data set.

Note:

Only two data sets can be used at a time in one step.

The observations in the base data set are not read.

PROC APPEND BASE = data-set

DATA = SAS-data-set;

RUN;



Example:

proc append base = store5 data = store4(drop= city store_size

Number_items_sold);

where Dollaramt le 30;

run;

Appending



Appending and Concatenating

DataSet 1

DataSet 2

Concatenating DataSet1 and DataSet2

Name Gender Age

Romina F 23

Flavia F 24

Anabella F 23

Cristian M 25

Francisco M 24

Name Gender Age

Eugenia F 24

Manuel M 24

Name Gender Age

Romina F 23

Flavia F 24

Anabella F 23

Cristian M 25

Francisco M 24

Eugenia F 24

Manuel M 24



Merging

Use the MERGE statement in a data step to join corresponding

observations from two or more data-sets.

General form of a DATA step match-merge:

A BY statement after the MERGE statement performs a match-merge

DATA data-set;

MERGE data-set (s);

BY variable (s);

< other SAS statements >;

Run;


20/24Confidential & Proprietary Copyright 2010 The Nielsen Company20AC BA HUB - Technical Team

proc sort data = storem1;

by store_id;run;


by store_id;

run;


by store_id;

run;data storemerge;

merge storem1 storem2 storem3;

by store_Id;

run;

Merging- Example



The OBS= Data set option

The OBS= data set option specifies an ending for processing an input data

set

This option specifies the number of the last observation to process, not

how many observation should be processed.

DATA selectstore;

SET store(OBS= 25);

Run;

The OBS= 25 option in the SET statement stops reading after observation

25 in the data set

SAS-data-set (OBS=n)



The FIRSTOBS= Data set option

The FIRSTOBS= data set option specifies a starting point for processing an input

data set

FIRSTOBS= and OBS= are often used together to define a range of observation

to be processed.

SAS-data-set (FIRSTOBS=n);



The FIRSTOBS= Data set option

DATA selectstore15;

SET store (FIRSTOBS= 11 OBS= 25);

Run;

The FIRSTOBS= and OBS= data set options in the SET statement read

15 observation from sas-data-set. The processing begins with observation

11 and ends after observation 25.


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THANK YOU!

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Data Step Programming

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