python - 向 csv 文件添加标题

Question

我有一堆已压缩的列表:

 zipped = zip(list1, list2, list3)

我有一个 csv 文件(已经有标题)，如下所示:

Col_1    Col_2    Col_3
data     data     data

现在我想将我的压缩列表添加为现有文件的列，使其看起来像这样(列表名称作为标题):

Col_1    Col_2    Col_3    list1    list2    list3
data     data     data     data     data     data

我现在有这个代码:

with open('existing.csv', 'rb') as infile, open('out_file.csv', 'wb') as outfile:
    reader = csv.reader(infile)
    writer = csv.writer(outfile)
    writer.writerow(["list1", "list2", "list3"])
    for i, row in enumerate(reader):
        row.extend(zipped[i])
        writer.writerow(row)

但是，不幸的是，这会覆盖现有的列名称。

Answer 1

您需要保留现有的标题，即读者对象的第一行:

with open('existing.csv', 'rb') as infile, open('out_file.csv', 'wb') as outfile:
    reader = csv.reader(infile)
    header = next(reader) # get header
    writer = csv.writer(outfile)
    # create list with old header and new
    writer.writerow(header+["list1", "list2", "list3"])

您还可以使用itertools.izip来压缩列表，在for循环中调用next来获取每个子元素:

from itertools import izip
zipped = izip(list1, list2, list3)
with open('existing.csv', 'rb') as infile, open('out_file.csv', 'wb') as outfile:
    reader = csv.reader(infile)
    headers = next(reader)
    writer = csv.writer(outfile)
    writer.writerow(headers+["list1", "list2", "list3"])
    for  row in  reader:
        row.extend(next(zipped))
        writer.writerow(row)

您自己的代码实际上不会覆盖 header ，它会添加您的新 header ，然后直接使用压缩列表中的第一个子元素压缩原始 header 。