如何使我的CSV/Excel文件从多个输出中编译数据？

Question

制作一个代码来扫描我的电子邮件，以寻找某种模式。我的目标是制作一个CSV文件，其中一个文件中列出了所有事件，但是我的代码仅将最后一封电子邮件添加到CSV中。这是输入：

pattern = re.compile(
            r"([a-zA-Z]+[0-9]+) Line ([0-9]+) Seq ([0-9]) ([0-9]+/[0-9]+/[0-9]+)")
matches = pattern.finditer(body)

with open("data.csv", "w") as f_out:
    writer = csv.writer(f_out)
    writer.writerows(map(lambda m: m.groups(), matches))

电子邮件通过以下内容：

第一封电子邮件：

PUU128378 Line 20 Seq 1 5/22/2023

PUN102939 Line 100 Seq 8 11/1/2024

PUU012939 Line 120 Seq 4 1/1/2025

第二封电子邮件：

PUU128377 Line 20 Seq 1 5/22/2023

PUN102938 Line 100 Seq 8 11/1/2024

PUU012938 Line 120 Seq 4 1/1/2025

excel文件看起来像：

我希望它看起来像：

​我的代码：

for i in range(messages, messages-N, -1):
    # fetch the email message by ID
    res, msg = imap.fetch(str(i), "(RFC822)")
    for response in msg:
        if isinstance(response, tuple):
            # parse a bytes email into a message object
            msg = email.message_from_bytes(response[1])
            # decode the email subject
            subject, encoding = decode_header(msg["Subject"])[0]
            if isinstance(subject, bytes):
                # if it's a bytes, decode to str
                subject = subject.decode(encoding)
            # decode email sender
            From, encoding = decode_header(msg.get("From"))[0]
            if isinstance(From, bytes):
                From = From.decode(encoding)
            print("Subject:", subject)
            print("From:", From)
            
            # if the email message is multipart
            if msg.is_multipart():
                # iterate over email parts
                for part in msg.walk():
                    # extract content type of email
                    content_type = part.get_content_type()
                    content_disposition = str(part.get("Content-Disposition"))
                    try:
                        # get the email body
                        body = part.get_payload(decode=True).decode()
                    except:
                        pass
                    
                    if content_type == "text/plain" and "attachment" not in content_disposition:
                        # print text/plain emails and skip attachments
                            pattern = re.compile(r"([a-zA-Z]+[0-9]+) Line ([0-9]+) Seq ([0-9]) ([0-9]+/[0-9]+/[0-9]+)")
                            matches = pattern.finditer(body)
                            with open("data.csv", "w") as f_out:
                                writer = csv.writer(f_out)
                                writer.writerows(map(lambda m: m.groups(), matches))
                            for match in matches:
                                print(match)

新编辑

with open("data.csv", "w") as f_out:
writer = csv.writer(f_out)

for i in range(messages, messages-N, -1):
    # fetch the email message by ID
    res, msg = imap.fetch(str(i), "(RFC822)")
    for response in msg:
        if isinstance(response, tuple):
            # parse a bytes email into a message object
            msg = email.message_from_bytes(response[1])
            # decode the email subject
            subject, encoding = decode_header(msg["Subject"])[0]
            if isinstance(subject, bytes):
                # if it's a bytes, decode to str
                subject = subject.decode(encoding)
            # decode email sender
            From, encoding = decode_header(msg.get("From"))[0]
            if isinstance(From, bytes):
                From = From.decode(encoding)
            print("Subject:", subject)
            print("From:", From)

                # iterate over email parts
            for part in msg.walk():
                # extract content type of email
                content_type = part.get_content_type()
                content_disposition = str(part.get("Content-Disposition"))
                payload = part.get_payload(decode=True)
                if payload is None:
                    continue
                body = payload.decode()
                    
                pattern = re.compile(
                    r"([a-zA-Z]+[0-9]+) Line ([0-9]+) Seq ([0-9]) ([0-9]+/[0-9]+/[0-9]+)")
                matches = pattern.finditer(body)
                writer.writerows(map(lambda m: m.groups(), matches))

Answer 1

您仅将最后一封电子邮件放入CSV文件的原因是因为您的代码 oftrites 每次处理消息时，任何现有的.csv文件。解决方案是仅在消息检索循环之外打开文件曾经的。

以下是您根据您在问题中添加的代码所建议的概述：

with open("data.csv", "w") as f_out:
    writer = csv.writer(f_out)
    pattern = re.compile(
        r"([a-zA-Z]+[0-9]+) Line ([0-9]+) Seq ([0-9]) ([0-9]+/[0-9]+/[0-9]+)")

    for i in range(messages, messages-N, -1):
        # fetch the email message by ID
        res, msg = imap.fetch(str(i), "(RFC822)")
        for response in msg:
            ...
            try:
                body = part.get_payload(decode=True).decode()
            except:  # NOTE it is bad to have non-specific except clauses like this.
                pass
            ...
            if content_type == "text/plain" and "attachment" not in content_disposition:
                # print text/plain emails and skip attachments
                matches = pattern.finditer(body)
                writer.writerows(map(lambda m: m.groups(), matches))
                for match in matches:
                    print(match)