csv.DictReader 中的行数

2022-01-10 00:00:00 python python-3.x iterator

问题描述

我有一个 csv DictReader 对象(使用 Python 3.1)，但我想知道阅读器在迭代之前包含的行数/行数.如下所示...

I have a csv DictReader object (using Python 3.1), but I would like to know the number of lines/rows contained in the reader before I iterate through it. Something like as follows...

myreader = csv.DictReader(open('myFile.csv', newline=''))

totalrows = ?

rowcount = 0
for row in myreader:
    rowcount +=1
    print("Row %d/%d" % (rowcount,totalrows))

我知道我可以通过遍历阅读器来获得总数，但是我无法运行for"循环.我可以遍历阅读器的副本，但我找不到如何复制迭代器.

I know I could get the total by iterating through the reader, but then I couldn't run the 'for' loop. I could iterate through a copy of the reader, but I cannot find how to copy an iterator.

我也可以用

totalrows = len(open('myFile.csv').readlines())

但这似乎是不必要的重新打开文件.如果可能，我宁愿从 DictReader 获取计数.

but that seems an unnecessary re-opening of the file. I would rather get the count from the DictReader if possible.

任何帮助将不胜感激.

艾伦

解决方案

rows = list(myreader)
totalrows = len(rows)
for i, row in enumerate(rows):
    print("Row %d/%d" % (i+1, totalrows))

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