将列表项拆分为 csv 列

Question

我正在尝试制作一个传输应用程序，它将获取文件名并将其转换为已发布文档的 csv 记录。目前，python 调用给定文件夹中的所有文件名，创建一个列表，并将文件名拆分为文档编号、修订版和标题。

目前我已经能够 python 抓取文件名，创建此信息的列表，然后拆分它们以创建新的单独数据列表，即 documentnumber ,revision,title.pdf 到 [文献编号、修订、标题].

    def getFiles():

    i = 0
    path = input("Paste in path for outgoing folder: ")
    numTitleRev = os.listdir(path)
    issueRec = []
    fileData = []
    totalList = len(numTitleRev)
    listNumber = str(totalList)
    print('\n' + "The total amount of documents in this folder is: " + listNumber + '\n')

    csvOutput = []

    while i < totalList:
        for item in numTitleRev:
            fileSplit = item.split(',', 2)
            fileTitle = fileSplit.pop(2)
            fileRev = fileSplit.pop(1)
            fileNum = fileSplit.pop(0)

        csvOutput.append([fileNum,fileRev,fileTitle])


        with open('output.csv', 'a') as writeCSV:
            writer = csv.writer(writeCSV)
            for row in csvOutput:
                writer.writerow(row)

        i += 1

    writeCSV.close()

    print("Writing complete")

The output I'm looking for is like so:
Number - Revision - Title
File1  - 01       - Title 1
File2  - 03       - Title 2 etc.

上面的代码是将列表和它的记录按'，'拆分的过程，这就是文件名在文件夹中的存储方式。

我认为下面代码的问题是 csvOutput 只将一个结果发送到 CSV，即字符串的最后一个结果。

然后在 csv 中打印文件夹中的文件总数，而不是拆分列表记录一，发送到 csv 重复记录二。

问题是当文件总数不恒定时，我想不出如何将这些信息存储为变量。

如有任何帮助，我们将不胜感激。

Answer 1

您应该在循环之前初始化 csvOutput = [] 并在每次迭代时更新它 csvOutput.append([fileNum,fileRev,fileTitle]) 这应该可以解决只存储最后一次迭代数据的问题。

我假设这是一个循环遍历你的数据 while i < totalList: 但你没有使用 i 计数器来提取正确的数据块，而是对相同的数据执行内部循环及以上。

如果你有非常量数据，你可以像在你的内部循环中一样迭代它，但这只是一个猜测，你需要提供准确的数据结构和你遇到的问题以获得更好的答案。

Answer 2

主要问题是嵌套的 while/for 循环。我对代码进行了一些重组，使其可以在本地进行测试（并且可以仅由 copy/pasting 运行）。这也应该让您了解如何构建代码以更轻松地寻求帮助。

我添加了很多评论来解释我所做的更改。

import csv

# This part has ben extracted from the main logic, to make the code runnable
# with sample data (see main() below)
def getFiles():
    path = input("Paste in path for outgoing folder: ")
    numTitleRev = os.listdir(path)
    print("\nThe total amount of documents in this folder is: %s\n" % len(numTitleRev))
    return numTitleRev


# This piece of logic contained the core error. The nested "while" loop was
# unnecessary. Additionally, the ".append" call wass on the wrong indent-level.
# Removing the unnecessary while-loop makes this much clearer
def process_files(filenames):
    parsed = []
    for item in filenames:
        # Using "pop()" is a destructive operation (it modifies the list
        # in-place which may leed to bugs). In this case it's absolutely fine,
        # but I replaced it with a different syntax which in turn also makes
        # the code a bit nicer to read.
        fileNum, fileRev, fileTitle = item.split(',', 2)
        parsed.append([fileNum,fileRev,fileTitle])
    return parsed


# Similarly to "getFiles", I extracted this to make testing easier. Both
# "getFiles" and "write_output" are functions with "side-effects" which rely on
# external resources (the disk in this case). Extracting the main logic into
# "process_files" makes that function easily testable without the need of
# having the files really exist on the disk.
def write_output(parsed_data):
    with open('output.csv', 'a') as writeCSV:
        writer = csv.writer(writeCSV)
        for row in parsed_data:
            writer.writerow(row)
    print("Writing complete")


# This is just a simple main function to illustrate how the new functions are
# called.
def main():
    filenames = [  # <-- Some example data to make the SO answer runnable
        '0,1,this is an example.txt',
        '1,4,this is an example.txt',
        '2,200,this is an example, with a comma in the name.txt',
        '3,1,this is an example.txt',
    ]
    # filenames = getFiles()  <-- This needs to be enabled for the real code
    converted = process_files(filenames)
    write_output(converted)

# This special block prevents "import side-effects" when this Python file would
# be imported somewhere else.
if __name__ == '__main__':
    main()

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