Records in Python

Records in Python

• 1.
  RECORDS IN PYTHON HigherComputing Science
• 2.
  RUNNER RECORD • Arecord is a special data structure which allows the programmer to combine multiple data objects • For example, a record might contain a string, an integer and a Boolean • Think again about the runner example • Instead of storing the name, bib number and elite status in three parallel arrays, these could be stored in a single record
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  RUNNER RECORD • Thepseudocode for the runner record is shown below: RECORD runner: name: string bib_number: integer elite: Boolean END RECORD
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  RUNNER RECORD • Toimplement this code in Python we use a dictionary runner = { 'name': 'John McGrain', 'bib_number': 1014, 'elite': False }
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  RUNNER RECORD • InPython, name, bib_number and elite are known as the dictionary keys runner = { 'name': 'John McGrain', 'bib_number': 1014, 'elite': False }
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  RUNNER RECORD • Weaccess dictionary keys like this: print(runner[‘name’]) -> John McGrain print(runner[‘bib_number’]) -> 1014
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  RUNNER RECORD • Weupdate the dictionary like this: runner[‘name’] = ‘Billy Jones’ print(runner) -> {'name': ‘Billy Jones’, 'bib_number': 1014,'elite': False}
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  ARRAY OF RECORDS •What if we want to store data about multiple runners? • Then we create an array • Instead of an array of integers, or an array of strings as we have seen previously, we create and array of records
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  ARRAY OF RECORDS •It would look like this: runners = [{'name': 'Ann', 'bib_number': 101, 'elite': False}, {'name': 'Jen', 'bib_number': 307, 'elite': True}, {'name': 'Tom', 'bib_number': 231, 'elite': False}] • Notice we have 3 records each separated by a comma • And these are all held within an array (we can tell by the square brackets)
• 10.
  ARRAY OF RECORDS •An array of records works in exactly the same way as any other array print(runners[0]) -> {'name': 'Ann', 'bib_number': 101, 'elite': False} print(runners[2]) -> {'name': 'Tom', 'bib_number': 231, 'elite': False}