如何根据正则表达式字符串拆分 pandas dataframe

Question

我有一个 CSV 的问题和结果。 构建了一些简单的代码来转换为数据帧列表以供分析。

但是最后一个拒绝拆分，我想是因为简单的 startswith 和 endswith 无法处理每个问题的 startswith 都以 "<Q" 开头的事实

def start_and_finish_points(df):
    df_indices_start = []
    df_indices_end = []
    rows = df.iloc[:, 0].to_list()
    for i, row in enumerate(rows):
        if str(row).startswith('<Q'):
            df_indices_start.append(i)
        if str(row).endswith('++'):
            df_indices_end.append(i)    
    return df_indices_start, df_indices_end
start, finish = start_and_finish_points(df) 

问题一是代码无法处理“<Q”

    question
    698 <Q8> To what extent are you concerned about of the following.................Climate change
    ... Some data
    700  <Q11e> How often d...

我可以概括 startswith 以处理字符串开头的空格吗？ 我确定它是正则表达式，但我看不到它。 更新：

The dataframe column that I want to extract from is this:

698    <Q8> To what extent are you concerned about of the following.................Climate change
699                                                                                               
700                                                                                All respondents
704                                                                                 Unweighted row
705                                                                          Effective sample size
706                                                                                          Total
707                                                                        1: Not at all concerned
710                                                                                              2
713                                                                                              3
716                                                                                              4
719                                                                              5: Very concerned
722                                                                                 Not applicable
725                                                                               Total: Concerned
728                                                                           Total: Not Concerned
731                                                                                Net % concerned
733                                                      95% lower case or +, 99% UPPER CASE or ++
735             <Q11e> How often do you access local greenspaces  (e.g. parks, community gardens)?
736                                                                                               
737                                                                                All respondents
741                                                                                 Unweighted row
742                                                                          Effective sample size
743                                                                                          Total
744                                                                           Hardly ever or never
747                                                                               Some of the time
750                                                                                          Often
753                                                                            (Prefer not to say)
Name: nan, dtype: object

[34]

Answer 1

此处避免正则表达式的一种方法是使用内置的strip方法，删除字符串前后的任何空格。

if str(row).strip().startswith('<Q'):