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python - 如何从字符串中拆分数据并将它们放入预定义的类别中？

问题描述

我正在尝试将以下存储在数组中的句子分成几类。这些类别是线路号、车站、关闭类型和日期，因为我正在抓取的所有地铁关闭公告都是这种格式。

"Line 1: Finch to Sheppard-Yonge nightly early closures March 23 to 26 - CANCELLED"
"Line 1: Lawrence to St Clair weekend closure Sunday, March 29 - REVISED"
"Line 1: Sheppard-Yonge to St Clair nightly early closures March 30 to April 2 - REVISED"9

例如：

Line = {0:"Line 1", 1:"Line 1", 2:"Line 1"}
Stations = {0: "Finch to Sheppard-Yonge", 1:"Lawrence to St Clair", 2:"Sheppard-Yonge to St Clair"}

我创建了一些非常复杂的 for 循环来执行此操作，但是，它们有很多错误，并且每个类别都需要不同的代码逻辑。下面是我如何从上述句子中提取“闭包类型”的示例，我假设有 3 种闭包类型存储在closure_types数组中：

closure_types = ["nightly early closures","single day closure","weekend closure"]
closure_types_split = []
for closure_type in closure_types:
    split_closure_type_a = closure_type.split()
    closure_types_split.append(split_closure_type_a)


closure_type_categorized = []
for i in range(len(split_closures)): 
    for ins in range(len(closure_types_split)):
        try:
            first_word_in_closure_types_split = closure_types_split[ins][0]
            first_word = split_closures[i].index(str(first_word_in_closure_types_split))
            if split_closures[i][first_word] == 'nightly':
                last_word = first_word + 3
                closure_type_categorized.append(split_closures[i][first_word:last_word])
            elif split_closures[i][first_word] == 'single':
                last_word = first_word + 2
                closure_type_categorized.append(split_closures[i][first_word:last_word])
            elif split_closures[i][first_word] == 'weekend':
                last_word = first_word + 2
                closure_type_categorized.append(split_closures[i][first_word:last_word])
        except:
            pass

我的问题是是否有更简单的方法来做我想做的事情？或者是否有任何 python 库旨在做我想做的事情？

标签： python

解决方案

这可以使用正则表达式来处理

import re

# note: spaces in the names must use `\s` (see St Clair), 
# because the re pattern uses verbose mode.
stations = '|'.join(line.strip() for line in 
    r"""
    Finch
    Lawrence
    Sheppard-Yonge
    St\sClair
    """.strip().splitlines())

# The re pattern is a raw f-string so the {stations} can be inserted.
pattern = rf"""(?ix)
    Line\s+(?P<line>\d+):
    \s*
    (?P<where>(?:{stations})(?:\s*to\s*(?:{stations}))*)    # one or more stations separated by 'to'
    \s*
    (?P<what>(?:\w*\s+)*?closures?)                         # phrase ending with closure or closures
    \s*
    (?P<when>[^-]*)                                         # everything up to a '-'
    \s*
    (?:-\s* (?P<note>.*))?                                  # if there is a '-' everything after it
    """

template = re.compile(pattern)

在测试用例上使用它：

testcases = [
    "Line 1: Finch to Sheppard-Yonge nightly early closures March 23 to 26 - CANCELLED",
    "Line 1: Lawrence to St Clair weekend closure Sunday, March 29 - REVISED",
    "Line 1: Sheppard-Yonge to St Clair nightly early closures March 30 to April 2 - REVISED",
]

for test in testcases:
    mo = template.search(test)
    print(mo.groupdict())

印刷：

{'line': '1', 'where': 'Finch to Sheppard-Yonge', 'what': 'nightly early closures', 'when': 'March 23 to 26 ', 'note': 'CANCELLED'}
{'line': '1', 'where': 'Lawrence to St Clair', 'what': 'weekend closure', 'when': 'Sunday, March 29 ', 'note': 'REVISED'}
{'line': '1', 'where': 'Sheppard-Yonge to St Clair', 'what': 'nightly early closures', 'when': 'March 30 to April 2 ', 'note': 'REVISED'}

对于更复杂的解析问题，我喜欢 TatSu 库。

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