How to print object data from OrderedCollection in Smalltalk

Question

I have a class in Smalltalk that stores an OrderedCollection of objects. Each object has a name. I would like to iterate over the OrderedCollection objects and print out the name of each of these objects. For example, in Java I would have something like:

for(int i = 0; i < array.length; ++i) {
  System.out.println(array[i].getName());
}

This is how far I got in Smalltalk, where "list" is the OrderedCollection:

1 to: list size do: [
:x | Transcript show: 'The object name:' list at: x printString; cr.
]

Answer 1

Your solution is good, except for two small mistakes: (1) you forgot some parenthesis and (2) the concatenation message #, is missing:

1 to: list size do: [
   :x | Transcript show: 'The object name:' list at: x printString; cr.
]

should have been

1 to: list size do: [
   :x | Transcript show: 'The object name:' , (list at: x) printString; cr.
]

otherwise the Transcript object would receive the message #show:at:, which it doesn't understand. Also, you have to concatenate the string 'The object name: ' with (list at: x) printString, and that's why you need the concatenation message #, in between.

Note however that in your example there is no need to use indexes. Instead of iterating from 1 to list size you could simply enumerate the objects in the list collection, like this:

list do: [:object | Transcript show: 'The object name: ' , object printString; cr]

This form is usually preferred because it avoids the use of an intermediate index (x in your example) and forces you to access the x-th element of the collection using #at:, all of which makes your code easier to read and modify.