To test whether a data variable contains at least one of a list of codes, type:

To test whether a data variable contains none of the listed codes, type:

To test whether a data variable contains exactly the given codes and nothing else, type:

To test whether a data variable contains exactly the given letter and nothing else, type:

To test whether two data variables contain identical codes, type:

To test whether a data variable contains codes other than those listed, type:

To test whether two data variables do not contain identical codes, type:

To check whether a column or data variable contains certain codes, place the codes, enclosed in single quotes, immediately after the name of the column or data variable. For example:

The expression:

checks whether a column (n) contains a certain code or codes (p). The expression is true as long as column n contains at least one of the given codes. It does not matter if there are other codes present since these are ignored.

For example, to check whether column 6 contains any of the codes 1 through 4,you type:

The expression is true if c6 contains any of the codes 1, 2, 3 or 4 or any combination of those codes, regardless of what other codes may also be present. For example:

are true, but:

is false.

The original example used the codes 1 through 4. You can, of course, use any codes you like and they can be entered in any order.

The opposite of cn’p’ is:

which checks that a column does not contain the given code or codes. The expression is true as long as the column does not contain any of the listed codes.

For example:

is true as long as column 478 does not contain a 5, 6, 7 or & or any combination of them. A multicode of ‘189’ returns the logical value true, because it does not contain any of the codes ‘5/7&’ whereas a multicode of ‘1589’ makes the expression false because it contains a ‘5’.

The = operator is used to check that the contents of a column are identical to either the given codes or the given letters.

The expression:

is true as long as c312 contains all of the codes 1 through 4 and 6, and nothing else. The expression:

checks that column 142 is blank. The equals sign is optional when checking for blanks, so you can write:

to check whether column 142 is blank.

The expression:

checks that column 124 contains the letter A and nothing else.

The = operator can also be used to compare the contents of two data variables. For example:

checks whether c56 contains exactly the same codes as c79. If so, the expression is true, otherwise it is false. If you have:

the expression is true, but:

yields the value false because column 79 contains a ‘9’ when column 56 does not.

If you have defined your own data variables, you could write a statement of the form:

to check whether the data variable called brand1 contains the same codes as c79.

The opposite of = is U (unequal):

This checks whether column n contains something other than just the code ‘p’. Suppose you have two sets of data:

and you write:

The expression is true for both sets of data. In the first example, the ‘7’ is multicoded with a ‘1’ and a ‘4’, while in the second example, column 34 does not contain a ‘7’ at all. The only time this expression is false is when column 34 contains a ‘7’ and nothing else.