Compare the variables x and z from the previous exercise using ==, identical() and all.equal(). For all.equal(), the tolerance level can be changed by passing a third argument, but what happens if the tolerance is set to 0?

Important: store the results of the four tests in the different objects chk1, chk2, chk3 and chk4!

(from: Cotton, 2013, Learning R, O’Reilly)