Python dictionaries - cheatsheet

In

Definition

  • Define dictionary (pairs key-value)

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    alien_0 = {
      'color': 'green',
      'points': 2
    }

  • Define empty dictionary

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    alien_0 = {}

  • Define ordered dictionary (keep order in which the data was entered)

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    from collections import OrderedDict 

    fav_languages = OrderedDict()  
    fav_languages['angeles'] = ['java', 'python']
    fav_languages['juan'] = ['php', 'java']

  • Get item

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    alien_color = alien_0.get('color')
    alien_points = alien_0.get('points', 0)

  • Get lenth

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    num_alien_traits = len(alien0)

Basic modifications

  • Add

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    alien_0['speed'] = 1.5

  • Modify

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    alien_0 = {
      'color': 'green',
      'points': 2
    }
    alien_0['color'] = 'purple'

  • Remove

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    del alien_0['points']

Iteration

  • Loop through items

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    for key, value in alien0.items():
      print(key + ": " + value)

  • Loop through keys

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    for key in alien0.keys():
      print("key: " + key)

    for key in sorted(alien0.keys()):
      print("key: " + key)

  • Loop through values

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    for value in alien0.values():
      print("value: " + value)