Method: String#scan

Defined in:

string.c

#scan(pattern) ⇒ Array #scan(pattern) {|match, ...| ... } ⇒ String

Both forms iterate through str, matching the pattern (which may be a Regexp or a String). For each match, a result is generated and either added to the result array or passed to the block. If the pattern contains no groups, each individual result consists of the matched string, $&. If the pattern contains groups, each individual result is itself an array containing one entry per group.

a = "cruel world"
a.scan(/\w+/)        #=> ["cruel", "world"]
a.scan(/.../)        #=> ["cru", "el ", "wor"]
a.scan(/(...)/)      #=> [["cru"], ["el "], ["wor"]]
a.scan(/(..)(..)/)   #=> [["cr", "ue"], ["l ", "wo"]]

And the block form:

a.scan(/\w+/) {|w| print "<<#{w}>> " }
print "\n"
a.scan(/(.)(.)/) {|x,y| print y, x }
print "\n"

produces:

<<cruel>> <<world>>
rceu lowlr

Overloads:

• #scan(pattern) ⇒ Array

  Returns:

  • (Array)
• #scan(pattern) {|match, ...| ... } ⇒ String

  Yields:

  • (match, ...)

  Returns:

  • (String)

# File 'string.c', line 9594

static VALUE
rb_str_scan(VALUE str, VALUE pat)
{
    VALUE result;
    long start = 0;
    long last = -1, prev = 0;
    char *p = RSTRING_PTR(str); long len = RSTRING_LEN(str);

    pat = get_pat_quoted(pat, 1);
    mustnot_broken(str);
    if (!rb_block_given_p()) {
	VALUE ary = rb_ary_new();

	while (!NIL_P(result = scan_once(str, pat, &start, 0))) {
	    last = prev;
	    prev = start;
	    rb_ary_push(ary, result);
	}
	if (last >= 0) rb_pat_search(pat, str, last, 1);
	else rb_backref_set(Qnil);
	return ary;
    }

    while (!NIL_P(result = scan_once(str, pat, &start, 1))) {
	last = prev;
	prev = start;
	rb_yield(result);
	str_mod_check(str, p, len);
    }
    if (last >= 0) rb_pat_search(pat, str, last, 1);
    return str;
}