Smalltalk - 用条件迭代字典数组

Question

I'm working on a Smalltalk small method, I want this method to iterate over a dictionary array and to return True or False depend on the conditions.

The dictionary array is an instance variable, name dictArray.

It looks like: [{'name': toto, 'age': 12}, {'name': tata, 'age': 25}]

So I want to iterate over dictArray and verify for each item the name and the age. If it matches I return true else false and the end of the iteration.

In python it should look like:

for item in dictArray:
    if item['name'] == aName and item['age'] == aAge:
        return True
return False

I can't find documentation with this special case (array iteration + condition + return)

Hope someone can help me!

Answer 1

To test whether a Collection contains an element that matches a condition, use anySatisfy: . It answers true iff there is a matching element.

dictArray anySatisfy: [:each | (each at: 'name') = aName and: [(each at: 'age') = anAge]]

Reference: https://www.gnu.org/software/smalltalk/manual-base/html_node/Iterable_002denumeration.html

The way described above is the preferred way to write it. The following is only for explanation how it relates to your Python code example.

anySatisfy: can be implemented in terms of do:

anySatisfy: aBlock
   self do: [:each | (aBlock value: each) ifTrue: [^ true]].
   ^ false

Or spelled out with your condition:

dictArray do:
   [:each |
   ((each at: 'name') = aName and: [(each at: 'age') = anAge])
      ifTrue: [^ true]].
^ false

This is the equivalent of your Python code.