AttributeError when trying to use seek() to get last row of csv file

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孤独总比滥情好
孤独总比滥情好 2020-12-19 15:57

I am trying to return the last row from a csv file. I am modifying another function that I wrote previously that returns the last line from a text file. It seemed to work

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  •  [愿得一人]
    2020-12-19 16:46

    Here's a slight variation of the core concept in the accepted answer to the question Have csv.reader tell when it is on the last line applied to your variation of the problem. Since each row is potentially a different length, there's really no way around having to read the whole file.

    import csv
    
    def get_last_row(csv_filename):
        with open(csv_filename, 'r') as f:
            lastrow = None
            for lastrow in csv.reader(f): pass
            return lastrow
    

    Update

    Here's a simpler and likely faster way to do it using a collections.deque. I got the idea from one of the answers to the question How to read an output line containing a list of integers produced.

    from collections import deque
    import csv
    
    def get_last_row(csv_filename):
        with open(csv_filename, 'r') as f:
            try:
                lastrow = deque(csv.reader(f), 1)[0]
            except IndexError:  # empty file
                lastrow = None
            return lastrow
    

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