SAS : Character Functions

This tutorial covers most frequently used SAS character functions with examples. It's a little bit tricky to deal character strings as compared to numeric values. Hence, it is required to know the practical usage of character functions.

1. COMPBL Function

It compresses multiple blanks to a single blank.

In the example below, the Name variable contains a record "Sandy   David". It has multiple spaces between the first and last name.

Create a dummy data

Data char;
Input Name $ 1-50 ;
Cards;
Sandy    David
Annie Watson
Hello ladies and gentlemen
Hi, I am good
;
Run;

Use COMPBL Function

Data char1;
Set char;
char1 = compbl(Name);
run;

Output

2. STRIP Function

It removes leading and trailing spaces.

Data char1;
Set char;
char1 = strip(Name);
run;

3. COMPRESS Function

SYNTAX 

COMPRESS(String, characters to be removed, Modifier)

Default - It removes leading, between and trailing spaces

Data char1;
Set char;
char1 = compress(Name);
run;

Output

Remove specific characters

data _null_;
x='ABCDEF-!1.234';
string=compress(x,'!4');put string=;
run;

It returns ABCDEF-1.23.

In SAS 9.1.3, the additional parameter called MODIFIER was added to the function.

The following keywords can be used as modifiers-

1. a – Remove all upper and lower case characters from String.
2. ak - Keep only alphabets from String.
3. kd - Keeps only numeric values
4. d – Remove numerical values from String.
5. i – Remove specified characters both upper and lower case from String.
6. k – keeps the specified characters in the string instead of removing them.
7. l – Remove lowercase characters from String.
8. p – Remove Punctuation characters from String.
9. s – Remove spaces from String. This is default.
10. u – Remove uppercase characters from String.

Example 1 : Keep only alphabets from alphanumeric values

data _null_;
x='ABCDEF-!1234';
string=compress(x,'','ak');put string=;
run;

It returns ABCDEF

Example 2 : Keep only numeric from alphanumeric

data _null_;
x='ABCDEF-!1234';
string=compress(x,'','kd');
put string=;
run;

It returns 1234

Example 3 : Remove all punctuation from string

data _null_;
x='ABCDEF-!1234';
string=compress(x,'','p');
put string=;
run;

It returns ABCDEF1234

Example 4 : Keep Integer Values from String

data _null_;
x='ABCDEF-!1.234';
string=compress(x,'0123456789.','k');put string=;
run;

It returns 1.234

4. LEFT Function

It moves leading blanks to the end of the value. The length of the string does not change.

Data char1;
Set char;
char1 = left(Name);
run;

5. TRIM Function

It removes trailing spaces.

Data char1;
Set char;
char1 = trim(Name);
run;

6. TRIM(LEFT(string))

It is equivalent to STRIP function. It first removes leading spaces and then trailing spaces.

7. CAT Function

It concatenates character strings. It is equivalent to || sign.

data _null_;
a = 'abc';
b = 'xyz';
c= a || b;
d= cat(a,b);
put c= d =;
run;

Both c and d returns "abcxyz".

Concatenate String and Numeric Value

data _null_;
x = "Temp";
y = 22;
z = x||y;
z1 = cats(x,y);
z2 = catx("",x,y);
put z = z1= z2 =;
run;

z = Temp          22 
z1=Temp22 
z2=Temp 22

Note -

1. The || keyword inserts multiple spaces when numeric and text values are concatenated.
2. CATS strips both leading and trailing blanks, and does not insert separators.
3. CATX strips both leading and trailing blanks, and inserts separators. The first argument to CATX specifies the separator.

8. SCAN Function

It extracts words within a value that is marked by delimiters.

SCAN( text, nth word, <delimiters>)

For example : 

We wish to extract first word in a sentence 'Hi, How are you doing?'. In this case, delimiter is a blank.

data _null_;
string='Hi, How are you doing?';
first_word=scan(string, 1, ' ' );
put first_word =;
run;

first_word returns 'Hi,' since it is the first word in the above sentence using blank as a delimiter.

We wish to extract last word in a sentence 'Hi, How are you doing?'. In this case, delimiter is a blank.

data _null_;
string='Hi, How are you doing?';
last_word=scan(string, -1, ' ' );
put last_word =;
run;

last_word returns 'doing?' since it is the last word in the above sentence.

Let's make it a little complicated.

Suppose, delimiter is a character instead of blank or special sign.

string='Hello SAS community people';
beginning= scan( string, 1, 'S' ); ** returns "Hello ";
middle = scan( string, 2, 'S' ); ** returns "A";
end= scan( string, 3, 'S' ); **returns " community people";

9. SUBSTR

It extracts strings based on character position and length. It is equivalent to MS Excel's MID Function.

= substr(old_var, starting_position, number of characters to keep);

Examples :

t="AFHood Analytics Group";
new_var=substr(t,8,9);
Result : Analytics

10. SUBSTR(Left of =) Function

It replaces a portion of string with new string

substr("old_variable",1,8) = new_data;
Result : New_dataable

11. LOWCASE, UPCASE and PROPCASE

LOWCASE converts the character string to lowercase.

UPCASE converts the character string to uppercase.

PROPCASE returns the word having uppercase in the first letter and lowercase in the rest of the letter (sentence format).


12. INDEX Function

It finds characters or words in a character variable

data _null_;
string='Hi,How are you doing?';
x = index(string, "How");
put x=;
run;

x returns 4 as "How" starts from 4th character.

To select all the records having 'ian' in their character.

if index(name,'ian') > 0;

To select all the records having first letter 'H'

if name =: 'H';

13. FIND Function

To locate a substring within a string

FIND (character-value, find-string <,'modifiers'> <,start>)

STRING1 = "Hello hello goodbye"

Examples :

1.  FIND(STRING1, "hello") returns 7

2.  FIND("abcxyzabc","abc",4) 7


14. TRANWRD Function

It replaces all occurrences of a word in a character string. It doesn't replace full phrase (entire value content).

TRANWRD (variable name, find what , replace with)

Example :  name : Mrs. Joan Smith

name=tranwrd(name, "Mrs.", "Ms.");

Result : Ms. Joan Smith


15. TRANSLATE Function

It replaces specific characters in a character expression

TRANSLATE(source, replace with, find what)

Examples:

x = translate('XYZW','AB','VW');

Result :  "XYZB"

Difference between TRANWRD and TRANSLATE Functions

The TRANSLATE function converts every occurrence of a user-supplied character to another character. TRANSLATE can scan for more than one character in a single call. In doing this, however, TRANSLATE searches for every occurrence of any of the individual characters within a string. That is, if any letter (or character) in the target string is found in the source string, it is replaced with the corresponding letter (or character) in the replacement string. 

The TRANWRD function differs from TRANSLATE in that it scans for words (or patterns of characters) and replaces those words with a second word (or pattern of characters).

16. PRXMATCH

It can be used for the following cases :

1. When you want to identify if there is alphanumeric (has any letter from A to Z) in a variable.
2. If you need to search a character variable for multiple different substrings.

PRXMATCH (perl-regular-expression, source);

Perl Regular Expression

1. ^ - start with 
2. $ - end with 
3. \D - any non digits 
4. \d - digits 
5. ? - may or may not have? 
6. | - or 
7. * - repeating 
8. ( i:) - turns ON the case insensitive search
9. (-i:) - turn OFF the case insensitive search

1. Check alphanumeric value

DATA test;
INPUT string $ 1-8;
prxmatch=prxmatch("/[a-zA-Z]/",string);
CARDS;
ACBED
11
12
zx
11 2c
abc123
;
run; 

Note : prxmatch("/[a-zA-Z]/",string) checks first character.


2. Replace multiple words with a new word

if prxmatch('/Luthir|Luthr|Luther/',name) then name='Luthra' ;

17. INPUT and PUT Function

INPUT Function is used to convert character variable to numeric.

new_num=input(character-variable, 4.);

Example - 

data temp;
x = '12345';
new_x = input(x,5.);
run;

In the above example, the variable x is a character variable as it is defined in quotes '12345'. The newly created variable new_x is in numeric format.

PUT Function is used to convert numeric variable to character.

new_char=put(numeric,4.0);

data temp;
x = 12345;
new_x = put(x,5.);
run;

In this example, the variable x is originally in numeric format and later converted to character in the new variable new_x.

18. LENGTH

It return length of a string.

data _null_;
x='ABCDEF-!1.234';
n= length(x);
put n=;
run;

It returns 13.

If you need to calculate the number of digits in a numeric variable -

First, we need to convert our numeric variable to character to count the number of digits as LENGTH function works only for character variable.

data _null_;
x = 12345;
cnt = length(strip(put(x,12.)));
put cnt=;
run;

In the above nested function, we first converted the variable x to character and then remove spaces by using STRIP function and then count number of digits by using LENGTH() function.

Another Method -

data _null_;
x = 12345;
cnt = int(log10(x)) + 1;
put cnt=;
run;

We can also use LOG10 function to solve it. LOG10 has a property which says :

Number of Digits = Integer value of [LOG10(x)] + 1. For example, LOG10(100) = 2 so Number of digits in 100 = 2 +1. See LOG10(1100) = 3.04 => INT(3.04) = 3 => 3+1 = Number of digits in 1100.

19. IF THEN
It replaces entire phrase.

20. COUNT Function

It counts the number of times that a specified substring appears within a character string.

data _null_;
name = "DeepAnshu Bhalla";
x = count(name,"a");
x1 = count(name,"a","i");
put x= x1=;
run;

Result :  x=2 as there are 2 lower case 'a's in the variable name. x1=3 as there are 3 'a's in the variable name (The 'i' modifier ignores case sensitivity)

21. COUNTW Function

It counts the number of words in a character string.

data readin;

input name$15.;

cards;

Trait Jhonson

3+3=6

;

run;

data out;

set readin;

x = countw(name);

x1 = countw(name,' ');

proc print;

run;

Output : COUNTW Function

 If you don't specify delimiter in the second parameter of COUNTW function, it would automatically special characters as a delimiter.

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Deepanshu founded ListenData with a simple objective - Make analytics easy to understand and follow. He has over 10 years of experience in data science. During his tenure, he has worked with global clients in various domains like Banking, Insurance, Private Equity, Telecom and Human Resource.

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