Before the Dot Becomes self: Writing a SimpleFraction Class

If `point.distance(self.center)` and `self.center.distance(point)` give the same answer, which object is really running the method?

Finger exercises

Short drills on what this video just taught. Write the code, run the checks, and reveal the answer only if you are stuck.

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Exercise 1 of 5

Which object is `self`?

Read this class and the two objects made from it — you do not need to retype any of it.

class Reservoir(object):
    def __init__(self, litres):
        self.litres = litres

    def surplus_over(self, other):
        return self.litres - other.litres

big = Reservoir(30)
small = Reservoir(12)

Work out what the call small.surplus_over(big) evaluates to, and assign that number to surplus.

# The number that call evaluates to.
surplus = ...  # your code here

# The number that call evaluates to.
surplus = ...  # your code here

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`surplus` is a number

reads the call in the direction it was written

matches what that call evaluates to

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Before the Dot Becomes self: Writing a SimpleFraction Class

Which object is self?

Before the Dot Becomes self: Writing a SimpleFraction Class

Which object is self?

Which object is `self`?

Which object is `self`?