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instance method

String#scan

scan(string_or_regexp) → array

scan(string_or_regexp) {|matches| ... } → self

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;
}

Matches a pattern against self; the pattern is:

string_or_regexp itself, if it is a Regexp.
Regexp.quote(string_or_regexp), if string_or_regexp is a string.

Iterates through self, generating a collection of matching results:

If the pattern contains no groups, each result is the matched string, $&.
If the pattern contains groups, each result is an array containing one entry per group.

With no block given, returns an array of the results:

Example

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

With a block given, calls the block with each result; returns self:

Example

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

Output:

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

See also #rstrip! #scrub #rstrip #scrub! also in 4.1 · 4.0 · 3.4 · 3.3 · 3.1 · 3.0

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