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