Method: String#capitalize!

Defined in:

string.c

#capitalize!(*options) ⇒ self^?

Upcases the first character in self; downcases the remaining characters; returns self if any changes were made, nil otherwise:

s = 'hello World!' # => "hello World!"
s.capitalize!      # => "Hello world!"
s                  # => "Hello world!"
s.capitalize!      # => nil

The casing may be affected by the given options; see Case Mapping.

Related: String#capitalize.

Returns:

# File 'string.c', line 8135

static VALUE
rb_str_capitalize_bang(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    OnigCaseFoldType flags = ONIGENC_CASE_UPCASE | ONIGENC_CASE_TITLECASE;

    flags = check_case_options(argc, argv, flags);
    str_modify_keep_cr(str);
    enc = str_true_enc(str);
    if (RSTRING_LEN(str) == 0 || !RSTRING_PTR(str)) return Qnil;
    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;
}