PCEP-30-02 3.3 Collect and Process Data Using Dictionaries PCEP-30 Practice Questions (Page 4)

Questions 16–19

1. 16foundation · easy

   Given `d = {'x': 1, 'y': 2}`, what is the result of executing `del d['x']`?

   • AA KeyError is raised
   • BThe dictionary becomes {'x': 1}
   • CThe dictionary becomes {'y': 2}
   • DThe dictionary becomes {'x': 1, 'y': 2}
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2. 17expert · hard

   A developer maintains a dictionary `cache = {'a': 1, 'b': 2, 'c': 3}`. The code must remove the LAST inserted key-value pair and return it as a tuple, but ONLY if the dictionary is not empty; otherwise it must return `None` without raising an error. Which code is correct?

   • A`result = cache.popitem() if cache else None`
   • B`result = cache.popitem() or None`
   • C`result = cache.pop(cache[-1])`
   • D`result = cache.popitem()`
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4. 18application · medium

   A dictionary `cache = {'a': 1, 'b': 2, 'c': 3}` is used as a simple cache. The developer must remove the key `'b'` if it exists, WITHOUT raising an error if it is absent. Which code is correct?

   • A`del cache['b']`
   • B`cache.pop('b', None)`
   • C`if 'b' in cache: del cache['b']`
   • D`cache.popitem()`
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5. 19application · medium

   A dictionary `settings = {'volume': 50, 'brightness': 70}` stores user preferences. The developer must increase the volume by 10, creating the key if it does not exist. Which code correctly updates the dictionary?

   • A`settings.update(volume=settings['volume'] + 10)`
   • B`settings['volume'] = settings.setdefault('volume', 0) + 10`
   • C`settings['volume'] = settings.get('volume', 0) + 10`
   • D`settings['volume'] += 10`
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