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instance method

String#downcase!

() -> self?

(:ascii | :fold | :lithuanian | :turkic) -> self?

(:lithuanian, :turkic) -> self?

(:turkic, :lithuanian) -> self?

downcase!(mapping) → self or nil

static VALUE
rb_str_downcase_bang(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    OnigCaseFoldType flags = ONIGENC_CASE_DOWNCASE;

    flags = check_case_options(argc, argv, flags);
    str_modify_keep_cr(str);
    enc = str_true_enc(str);
    if (case_option_single_p(flags, enc, str)) {
        if (downcase_single(str))
            flags |= ONIGENC_CASE_MODIFIED;
    }
    else if (flags&ONIGENC_CASE_ASCII_ONLY)
        rb_str_ascii_casemap(str, str, &flags, enc);
    else
        str_shared_replace(str, rb_str_casemap(str, &flags, enc));

    if (ONIGENC_CASE_MODIFIED&flags) return str;
    return Qnil;
}

Like String#downcase, except that:

Changes character casings in self (not in a copy of self).
Returns self if any changes are made, nil otherwise.

Related: See Modifying.

See also #downcase #dump #delete_suffix! #each_byte also in 4.0 · 3.4 · 3.3 · 3.2 · 3.1 · 3.0

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