import csv r = csv.reader(open('file.csv')) first_row = r.next() for row in r: i... | Hacker News

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pstrateman on June 12, 2015 | parent | context | favorite | on: Inverting Binary Trees Considered Harmful

    import csv
    
    r = csv.reader(open('file.csv'))
    first_row = r.next()
    for row in r:
        if row[0] == first_row[0]:
            return True
    return False

287MB file 100m rows 15.804s peak memory usage 7MB

xamuel on June 12, 2015 [–]

Thank you, that is beautiful. I've been proved decisively wrong and I've gained some greater appreciation for python's libraries.

TylerE on June 12, 2015 | [–]

It's not even a library thing. Reading a file in this way does reads in approximately optimal (for the FS) sized blocks. The CSV parser just rides on top of stdio.

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