# Julia, <s>28</s> 27 bytes

    x->colon(extrema(x)...)∩x

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[Try it online!]: http://julia.tryitonline.net/#code=ZiA9IHgtPmNvbG9uKGV4dHJlbWEoeCkuLi4p4oipeAoKcHJpbnQoZihbOTksLTIsNTMsNCw2Nyw1NSwyMyw0Myw4OCwtMjIsMzYsNDVdKSk&input=