Variable Type Conversions

If you define a numeric variable and assign the result of a character expression to it, SAS tries to convert the character result of the expression to a numeric value and to execute the statement. If the conversion is not possible, SAS prints a note to the log, assigns the numeric variable a value of missing, and sets the automatic variable _ERROR_ to 1. For a listing of the rules by which SAS automatically converts character variables to numeric variables and vice-versa, see "Automatic Numeric-Character Conversion" on page 116.

If you define a character variable and assign the result of a numeric expression to it, SAS tries to convert the numeric result of the expression to a character value using the BEST w. format, where w is the width of the character variable and has a maximum value of 32. SAS then tries to execute the statement. If the character variable you use is not long enough to contain a character representation of the number, SAS prints a note to the log and assigns the character variable asterisks . If the value is too small, SAS provides no error message and assigns the character variable the character zero (0).

Output 5.1: Automatic Variable Type Conversions (partial SAS log)

 4     5           data _null_;     6             x= 3626885;     7             length y $ 4;     8             y=x;     9             put y;     36E5     NOTE: Numeric values have been converted to character           values at the places given by:           (Number of times) at (Line):(Column).           1 at 8:5     10         data _null_;     11           xl= 3626885;     12           length yl $ 1;     13           yl=xl;     14           xs=0.000005;     15           length ys $ 1;     16           ys=xs;     17           put yl= ys=;     18         run;     NOTE: Invalid character data, XL=3626885.00 ,           at line 13 column 6.     YL=* YS=0     XL=3626885 YL=* XS=5E-6 YS=0 _ERROR_=1 _N_=1     NOTE: Numeric values have been converted           to character values at the places           given by: (Number of times) at           (Line):(Column).           1 at 13:6           1 at 16:6 

 

In the first DATA step of the example, SAS is able to fit the value of Y into a 4-byte field by representing its value in scientific notation. In the second DATA step, SAS cannot fit the value of YL into a 1-byte field and displays an asterisk (*) instead.