trying to retrieve element from an OrderedCollection

Question

I am using pharo. I have a Car class which has a speed variable and the class side method withSpeed: aSpeed which sets speed := aSpeed.

I am trying the following test in the playground.

car := Car withSpeed: 20.
cars := OrderedCollection new.
cars add: car.

Now, I have a car inside cars collection.

I want to get the car which has speed = 20 I am trying the following code, but it gives me error:

result := cars select: [ :each | each withSpeed: 20. ].  

Any idea what is going wrong?

Answer 1

Given that your Car has an accessor for speed, you simply can do

result := cars select: [ :each | each speed = 20. ].  

That gets you all cars that have the speed 20. If you only want one, you should use detect:

myCar := cars detect: [ :each | each speed = 20. ].  

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Accessors for instance variables (here speed) typically look like

Car>>speed
    ^ speed

and

Car>>speed: anObject
    speed := anObject.