file_ls

Return the names of all files member of a given directory.

%let list = %file_ls(dir, match=, nomatch=, ext=, beg=no, end=no, casense=yes, excldir=no);

Arguments

• dir : a directory full path;
• match : (option) inclusion pattern for the name of the members (files and directories, also depending on parameter excldir below) searched for; for instance, you may wish to list all files starting with "table_" passingmatch=table_`; default: empty, no pattern is defined, the macro will search for all members without restriction;
• nomatch : (option) exclusion pattern for the name of the members searched for; NOT IMPLEMENTED YET;
• ext : (option) extension of the members searched for; default: no extension, the macro will search for all members without consideration for the extension;
• beg : (option) boolean flag (yes/no) set to force the matching of the match string at the beginning of the filenames; default: beg=no, i.e. a match with the match string is looked for anywhere in the filenames whenever end=no as well (see below);
• end : (option) ibid with the end of the filenames; end is incompatible with beg (see above); default: end=no, i.e. a match with the match string is looked for anywhere in the filenames;
• casense : (option) boolean flag (yes/no) set to perform cases sensitive search/matching; default: casense=yes, i.e. the pattern match will be searched/matched exactly;
• excldir : (option) boolean flag (yes/no) set to exclude subdirectories from the search; default: excldir=no, i.e. sub-directories, when they exist, are also searched for (and matched against all search criteria above);
• sep : (option) output list separator; default: sep=%quote( ), i.e. a blank separator is used.

Returns

list : list of the files member of the directory dir matching the constraints on match and/or ext when passed as parameters.

Examples

let us test the current file (file_ls.sas):

%let dir=&G_PING_ROOTPATH/library/autoexec;
%let ext=sas;
%let pattern=file_ls;

then running:

%let list=%file_ls(&dir, match=&pattern, ext=&ext);

returns list=file_ls, while running:

%let list=%file_ls(&dir, match=&pattern);

returns list=file_ls.sas, and running:

%let list=%file_ls(&dir);

returns in list the list of all files present in the directory &G_PING_ROOTPATH/library/autoexec. The options beg/end can be further used to specified the type of matching, e.g.:

%let dir=&G_PING_ROOTPATH/library/autoexec;
%let beg=yes;
%let ext=sas;
%let pattern=list;
%let list=%file_ls(&dir, match=&pattern, beg=&beg, ext=&ext);

returns in list the list of all files present in the directory &G_PING_ROOTPATH/library/autoexec whose names start with the pattern list; in particular the file list_quote will be returned in list, but not clist_unquote will not.

Run macro %_example_file_ls for more examples.

Notes

1. This macro enables the user to list the files in a given folder, either SAS tables or any other types of files. This is typically useful when dealing with massive imports of CSV/txt files.
2. Note, like in the example above, that in the case you specify an extension ext, the macro automatically omits the extension in the output list. Otherwise, the name of the files are provided with their extensions.
3. In practice, the same identical output can be retrieved using the macro %dir_ls using the following commands:

%let list=; 
%let tmp=;
%dir_ls(&dir*&pattern*&ext, dsn=TMP);
%var_to_list(TMP, base, _varlst_=tmp);
%do i=1 %to %list_length(&tmp, sep=%str( ));
     %let list=&list %file_name(%scan(&tmp,&i,%str( )), res=base);
%end;

Note that, contrary to %dir_ls that works only on non-Windows machines, this macro runs on all platforms/systems.

1. In the case that beg=yes and end=yes, the macro looks for filenames matching exactly match.

References

Hamilton, J.(2012): "Obtaining a list of files in a directory using SAS functions".

See also

%dir_ls, %dir_check, %file_name, FEXIST, FILENAME, DOPEN, DNUM, DREAD.