Hacker News Reader

Comment by jasonlotito | Hacker News Reader

Just curious, for comparison: what would the equivalent be in Ruby?

    filteredArray = [allRecords filteredArrayUsingPredicate:
        [NSPredicate predicateWithFormat:@"someField == %d",   someFieldFilterValue]];

in ruby:

    all_records.select {|r| r.some_field == some_field_filter_value}

in clojure:

    (filter #(= % some-filter-value) all-records)

in haskell:

    filter (\someField -> x == someFilterValue) allRecords

Let's be fair, in Objective-C, this could be actually more like

  NSIndexSet *indicies = [allRecords indexesOfObjectsPassingTest:^ (id obj, NSUInteger idx, BOOL *stop) { return [obj someField] == someFieldFilterValue; }];
  filteredArray = [allRecords objectsAtIndexes:indicies];

rather than what the article had in mind.

EDIT: oh, someFieldFilterValue was an integer, wasn't it. Fixed.

my_array.select { |item| item == somefiltervalue }

At least that's one way to do it in ruby.

Reply on news.ycombinator.com