String#%

(::array[untyped] positional_args) -> ::String

(::hash[::Symbol, untyped] named_args) -> ::String

(untyped arg) -> ::String

string % object → new_string

static VALUE
rb_str_format_m(VALUE str, VALUE arg)
{
    VALUE tmp = rb_check_array_type(arg);

    if (!NIL_P(tmp)) {
        return rb_str_format(RARRAY_LENINT(tmp), RARRAY_CONST_PTR(tmp), str);
    }
    return rb_str_format(1, &arg, str);
}

Returns the result of formatting object into the format specification self (see Kernel#sprintf for formatting details):

Example

"%05d" % 123 # => "00123"

If self contains multiple substitutions, object must be an Array or Hash containing the values to be substituted:

Example

"%-5s: %016x" % [ "ID", self.object_id ] # => "ID   : 00002b054ec93168"
"foo = %{foo}" % {foo: 'bar'} # => "foo = bar"
"foo = %{foo}, baz = %{baz}" % {foo: 'bar', baz: 'bat'} # => "foo = bar, baz = bat"

See also .try_convert #* .new #+ also in 4.1 · 4.0 · 3.3 · 3.2 · 3.1 · 3.0

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