list_compare

Compare two lists of characters/strings, i.e check whether the items in one list differ from those in another not taking into account any order or repetition(s).

%list_compare(list1, list2, casense=no, sep=%quote( ));

Arguments

• list1, list2 : two lists of items;
• casense : (option) boolean flag (yes/no) set to perform cases sensitive search/matching; default: casense=no, i.e. the upper-case elements in both lists are matched;
• sep : (option) character/string separator in input list; default: %quote( ), i.e. items are separated by a blank.

Returns

ans : the boolean result of the comparison test of the "sets" associated to the input lists, i.e.:

• 0 when both lists are equal: list1 = list2,
• -1 when list1 items are all included in list2 (but the opposite does not stand): say it otherwise: list1 < list2,
• 1 when list2 items are all included in list1 (but the opposite does not stand): say it otherwise: list1 > list2,
• (i.e. ans=) when they differ.

Examples

Simple examples (with casense=yes by default):

%let list1=NL UK DE AT BE;
%let list2=DE AT BE NL UK SE;
%let ans=%list_compare(&list1, &list2);

returns ans=-1, while:

%let ans=%list_compare(&list2, &list1);

returns ans=1, and:

%let list1=NL UK DE AT BE;
%let list2=DE NL AT UK BE;
%let ans=%list_compare(&list1, &list2);

returns ans=0. We also further use the case sensitiviness (yes/no) for comparison:

%let list1=NL uk de AT BE;
%let list2=DE NL at UK be;
%let ans1=%list_compare(&list1, &list2, casense=yes);
%let ans2=%list_compare(&list1, &list2);

return ans1= (i.e. list differ) and ans2=0 (i.e. lists are equal with default casense=no).

Run macro %_example_list_compare for examples.

Notes

• If one of the lists is empty, then the result is empty (set to ans=).
• If elements are duplicated in a list, %list_compare may still return 0, for instance:

    %let list1=NL DE AT BE;
    %let list2=DE AT NL BE NL BE;
    %let ans=%list_compare(&list1, &list2);
  

  returns ans=0...

See also

%clist_compare, %list_remove, %list_count, %list_slice, TRANWRD, FINDW.