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Accepted
Dan
Asked: 2023-12-07 23:41:14 +0800 CST

列的正则表达式不产生预期输出

  • 772

我有这个数据框：

dfsupport = pd.DataFrame({'Date': ['8/12/2020','8/12/2020','13/1/2020','24/5/2020','31/10/2020','11/7/2020','11/7/2020'],
                          'Category': ['Table','Chair','Cushion','Table','Chair','Mats','Mats'],
                          'Sales': ['1 table','3chairs','8 cushions','3Tables','12 Chairs','12Mats','4Mats'],
                          'Paid': ['Yes','Yes','Yes','Yes','No','Yes','Yes',],
                          'Amount': ['93.78','$51.99','44.99','38.24','£29.99','29 21 only','18']
                          })

以表格形式显示如下：

          Date Category     Sales   Paid      Amount
0   8/12/2020    Table     1 table  Yes       93.78
1   8/12/2020    Chair     3chairs  Yes      $51.99
2   13/1/2020  Cushion  8 cushions  Yes       44.99
3   24/5/2020    Table     3Tables  Yes       38.24
4  31/10/2020    Chair   12 Chairs   No      £29.99
5   11/7/2020     Mats      12Mats  Yes  29 21 only
6   11/7/2020     Mats       4Mats  Yes          18

我想删除上面的两个字符串元素。我学会了如何成功地将 $ 和 £ 替换为：

patternv='|'.join(re.escape(x) for x in ['$', '£'])
dfsupport['Amount'] = dfsupport['Amount'].str.replace(patternv,regex=True)

我现在想要替换“金额”列中包含“29 21 only”的条目。我的尝试是：

patterns="{r'(\d{1,})\s(\d{1,2})\D+' : r'\1 \2'}"
dfsupport['Amount']=dfsupport['Amount'].str.replace(patterns,regex=True)

但是我的尝试导致了错误：

Traceback (most recent call last):
  File "/home/cloud/code/learning/howmany.py", line 160, in <module>
    dfsupport['Amount'] = dfsupport['Amount'].str.replace(patternv,regex=True)
                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/cloud/.venv/lib/python3.12/site-packages/pandas/core/strings/accessor.py", line 136, in wrapper
    return func(self, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: StringMethods.replace() missing 1 required positional argument: 'repl'

我该如何解决？

我应该补充一点，我正在寻求输出为“29.21”

我在这里关注了这个问题

python

1 个回答

  1. Best Answer

    您缺少第二个（强制）参数str.replace：

    dfsupport['Amount'] = dfsupport['Amount'].str.replace(r'(\d{1,})\s(\d{1,2})\D+',
                                                      r'\1.\2', regex=True)

    似乎您正在尝试在 中使用字典patterns，但这并不像您那样工作，您必须传递一个正则表达式。

    如果你想传递字典，请使用replace（不带str.）：

    patterns = {r'(\d{1,})\s(\d{1,2})\D+' : r'\1.\2'}
dfsupport['Amount'] = dfsupport['Amount'].replace(patterns,regex=True)

    输出：

             Date Category       Sales Paid  Amount
0   8/12/2020    Table     1 table  Yes   93.78
1   8/12/2020    Chair     3chairs  Yes  $51.99
2   13/1/2020  Cushion  8 cushions  Yes   44.99
3   24/5/2020    Table     3Tables  Yes   38.24
4  31/10/2020    Chair   12 Chairs   No  £29.99
5   11/7/2020     Mats      12Mats  Yes   29.21
6   11/7/2020     Mats       4Mats  Yes      18
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