str_isvar

Define if a (list of) string(s) actually define variables in a given dataset.

%str_isvar(dsn, var, _ans_=, _var_=, lib=WORK, sep=%str( ));

Arguments

• dsn : a reference dataset;
• var : list of string elements to be from the dataset when they exist;
• lib : (option) name of the input library; by default: WORK is used;
• sep : (option) character/string separator in input var list; default: %str( ), i.e. sep is blank.

Returns

• _ans_ : (option) name of the macro variable storing the list of same length as var where the i-th item provides the answer of the test above for the i-th item in var, i.e.:
  • 1 if it is the name of a variable in var,
  • 0 if not; either this option or the next one (_var_) must be set so as to run the macro;
• _var_ : (option) name of the macro variable storing the updated list from which all elements that do not macth existing variables/fields in dsn have been removed.

Example

Let us consider the table _dstest5:

f	e	d	c	b	a
.	1	2	3	.	5

then:

%let var=a b y z c;
%let ans=;
%let list=;
%str_isvar(_dstest5, &var, _ans_=ans, _var_=list);

returns ans=1 1 0 0 1 and list=a b c, the only string elements of var which define variables in _dstest5.

Run macro %_example_str_isvar for more examples.

Note

1. In short, this macro "intersects" the list var with the list of variables in dsn, i.e. running:

%let allvars=;
%ds_contents(&dsn, _varlst_=allvars, lib=&lib);
%let &_var_=%list_intersection(&var,  &allvars);

1. The order of the variables in the output list matches that in the input list var.
2. When none of the string elements in var matches a variable in dsn, an empty list is set.

See also

%str_isgeo, %ds_contents, %var_check, %ds_check.