zip combines corresponding elements from two or more iterables into tuples, stopping when the shortest iterable ends. It is useful when parallel data must be processed together. section 8.8
x = [1, 2, 3, 4] y = ['a', 'b', 'c'] #1 z = zip(x, y) list(z) [(1, 'a'), (2, 'b'), (3, 'c')] #2 #1 y is three elements; x is four elements. #2 z has only three elements.
With x containing four values and y containing three, list(zip(x, y)) produces three pairs: (1, 'a'), (2, 'b'), and (3, 'c'). section 8.8
Use zip when:
- Parallel lists need to be treated as paired records. section 8.8
- An iterator is suitable for streaming rows into a writer rather than building a list first. section 22.5.2
- You need to remember that converting the result with list() materializes the pairs for inspection. section 22.5.2
Writing paired weather data
Extract parallel time and temperature lists, then write paired rows with for time, temperature in zip(time_data, temperature_data): writer.writerow([time, temperature]). The same iterator can be passed directly to writerows().
