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instance method

BasicObject#!

!obj → true or false

MJIT_FUNC_EXPORTED VALUE
rb_obj_not(VALUE obj)
{
    return RTEST(obj) ? Qfalse : Qtrue;
}

Boolean negate.

See also #!= .new #== also in 4.1 · 4.0 · 3.4 · 3.3 · 3.2 · 3.1