Question

作为“数据结构”课程的一部分，我的老师给了我额外的练习，这有点困难和挑战。我试图找出用于解决此问题的数据结构，但我没有任何想法，我也想尝试自己编写代码以提高自己的python技能。

关于练习： 1.我有一个带有日志的文本文件，如下所示：

M, 1, 14/08/2019 11:39, 4, xxxx, username, “Initialization of the system, and loading
M, 1, 14/08/2019 11:40, 100, xxxx, username, “Open Connection”
M, 1, 14/08/2019 11:40, 100, xxxx, username, “Close Connection, and reboot”
S, 1, 14/08/2019 11:40, 6, xxxx, New User, We created the user in the systems
S, 1, 14/08/2019 11:41, 3, xxxx, User logged in, User username logged in
M, 1, 14/08/2019 11:39, 4, xxxx, username, “Initialization of the system”
S, 1, 14/08/2019 11:40, 6, xxxx, New User, We created the user in the systems
S, 1, 14/08/2019 11:41, 3, xxxx, User logged in, User username logged in

有2种日志，M是Master，S是Slave。我需要一个数据结构，该数据结构将能够拆分每一行并将其抓取到特定的列中。即M-1列将为：

M, 1, Datetime, Error Level, DeviceId, UserId, Message

但S-1列为：

S, 1, Datetime, Error Level, DeviceId, Action, Message

注意：如您所见，S，1中有Action，但没有UserId。

最后，我需要做的是在命令行中输入我要标准输出的列和条件（即错误级别> 50）。

我最想知道的是字典，但是这样一来，我将无法支持无限数量的版本（如果可能的话，请向我解释方式）。

谢谢！

Answer 1

我可能会使用namedtuple包中的collections类来保存每个已解析的项目，因为它允许您通过索引号和名称来访问每个字段。此外，可以通过传递列名列表来轻松地动态创建新的namedtuple类。

from collections import namedtuple

Master = namedtuple('Master', ['Type', 'N', 'Datetime', 'ErrorLevel', 'DeviceId', 'UserName', 'Message'])
Slave = namedtuple('Slave', ['Type', 'N', 'Datetime', 'ErrorLevel', 'DeviceId', 'Action', 'Message'])

n_cols = 7

logfileasstring = """
M, 1, 14/08/2019 11:39, 4, xxxx, username, “Initialization of the system, and loading
M, 1, 14/08/2019 11:40, 100, xxxx, username, “Open Connection”
M, 1, 14/08/2019 11:40, 100, xxxx, username, “Close Connection, and reboot”
S, 1, 14/08/2019 11:40, 6, xxxx, New User, We created the user in the systems
S, 1, 14/08/2019 11:41, 3, xxxx, User logged in, User username logged in
M, 1, 14/08/2019 11:39, 4, xxxx, username, “Initialization of the system”
S, 1, 14/08/2019 11:40, 6, xxxx, New User, We created the user in the systems
S, 1, 14/08/2019 11:41, 3, xxxx, User logged in, User username logged in"""


master_list = []
slave_list = []

for r in logfileasstring.splitlines(False):
    if not r:
        continue
    values = [value.strip() for value in r.split(',', n_cols - 1)]
    if r[0] == 'M':
        master_list.append(Master(*values))
    else:
        slave_list.append(Slave(*values))


print(master_list[0][6]) # by index
print(master_list[0].Message) # by column name if name known in advance
column_name = 'Message'
print(master_list[0].__getattribute__(column_name)) # by column name if name not known in advance

Run demo

Answer 2

此帮助：

logfileasstring = """
M, 1, 14/08/2019 11:39, 4, xxxx, username, “Initialization of the system, and loading
M, 1, 14/08/2019 11:40, 100, xxxx, username, “Open Connection”
M, 1, 14/08/2019 11:40, 100, xxxx, username, “Close Connection, and reboot”
S, 1, 14/08/2019 11:40, 6, xxxx, New User, We created the user in the systems
S, 1, 14/08/2019 11:41, 3, xxxx, User logged in, User username logged in
M, 1, 14/08/2019 11:39, 4, xxxx, username, “Initialization of the system”
S, 1, 14/08/2019 11:40, 6, New User, We created the user in the systems
S, 1, 14/08/2019 11:41, 3, User logged in, User username logged in"""
listoflist = [[v.strip() for v in r.split(",", maxsplit=6)]
               for r in logfileasstring.splitlines(keepends=False) 
               if r]

grouped = {("M", "1"): [], ("S", "1"): []}
for row in listoflist:
    datasets_for = grouped[row[0], row[1]]
    datasets_for.append(row[2:])


# must be set by script
fields = [0, 1, 2]
for k in grouped:
    print(k, "::")
    for row in grouped[k]:
        print("  -", [row[f] for f in fields])

锻炼的数据结构建议

2 个答案: