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Ruby

Posted by TJ Takei
TJ Takei
13,362 Points

Isn't "if ...size>0" guard unnecessary for ...each loop? (Ruby Dev Tools)

For containers' "each" method to work, apparently "if (container).size>0" guard seems unnecessary, as long as it is initially set empty. So a code snippet below considered not so educational, is it?

if contact["phone"].size > 0
  contact["phone"].each do |item| ... end
end

in "Part 3: Printing The Contact List" video of "Build a Simple Contact List" lecture of Development Tools

1 Answer

Zachary Green
Zachary Green
16,359 Points
Zachary Green
Zachary Green
16,359 Points

you can use the if statment to maybe tell the user that there is no info to show. I would keep it like that unless you know that contact['phone'] will always have some value in it.

TJ Takei
TJ Takei
13,362 Points

Yes, I agree if and only if we need to do anything with the container itself. However, the "do" block in the lecture has nothing with the container, and it does process something for each item in it. In addition, the "each" loop works even in the case of empty container, that is, it does nothing. Therefore I believe we better refactor the requirement for the container processing and that for the items in it.

Understandably, in the real world situations, many cases require the checking of empty containers. For those the separate "if ...size > 0" would be best practice. Yet, for educational purposes, in the text I would avoid to leave an impression that the "if ...size > 0" guard looks mandatory for the "...each" loop to work. By doing so, it would show the students the power of the "...each" loop to include the empty case.