Python 2.7 如何在python（2.7）中更改csv文件的标题？

我是一名初学者，在csv文件中有以下数据，我想将“帐户密钥”更改为“帐户”。我该怎么做呢

帐户密钥、状态、加入日期、取消日期、取消天数、是否取消 448，取消，2014-11-102015-01-14,65，正确 448，取消，2014-11-052014-11-10,5，正确 ... ...

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如果文件足够小，可以放入主内存：

import csv

with open('path/to/file') as infile:
    data = list(csv.reader(infile))
data[0][0] = 'acct'

with open('path/to/file', 'w') as fout:
    outfile = csv.writer(fout)
    outfile.writerows(data)

with open('path/to/file') as fin, open('path/to/output', 'w') as fout:
    infile = csv.reader(fin)
    header = next(infile)
    header[0] = 'acct'
    outfile.writerow(header)
    for row in infile:
        outfile.writerow(row)

如果文件太大，无法放入主内存：

import csv

with open('path/to/file') as infile:
    data = list(csv.reader(infile))
data[0][0] = 'acct'

with open('path/to/file', 'w') as fout:
    outfile = csv.writer(fout)
    outfile.writerows(data)

with open('path/to/file') as fin, open('path/to/output', 'w') as fout:
    infile = csv.reader(fin)
    header = next(infile)
    header[0] = 'acct'
    outfile.writerow(header)
    for row in infile:
        outfile.writerow(row)