基于字符串逐行的熊猫数据框上的 ifelse

Question

这很简单。任务是检查一列中的字符串是否包含存储在另一个字符串中的所有单词。基于此做一些事情。这是一个简单的例子

import pandas as pd

df = pd.DataFrame({'Strings':["The brown","fox smoked 6", "cigarettes per day", "in his cave"], 
'Set': ["Alpha", "Beta", "Gamma", "Delta"]})

... >>> df
     Set             Strings
0  Alpha           The brown
1   Beta        fox smoked 6
2  Gamma  cigarettes per day
3  Delta         in his cave
>>> 

现在我想检查 df["Strings"] 的每一行是否包含单词“smoked”和数字“6”（这里的第 3 行也是如此）。如果是这样，我需要新列 df["Result"] 等于 df["Set"] 但添加了“健康损害”字样。如果不只是复制 df["Set"] 中包含的内容。输出应如下所示：

... >>> df_final
     Set             Strings   Result
0  Alpha           The brown   Alpha
1   Beta        fox smoked 6   Beta health damaging
2  Gamma  cigarettes per day   Gamma
3  Delta         in his cave   Delta
>>>  

Answer 1

您可以构建您的 2 个条件的掩码并将其传递给 np.where：

In [20]:

mask = (df['Strings'].str.contains('6')) & (df['Strings'].str.contains('smoked'))
In [23]:

et
df['Result'] = np.where(mask, df['Set'] + ' health damaging', df['Set'])
df
Out[23]:
     Set             Strings                Result
0  Alpha           The brown                 Alpha
1   Beta        fox smoked 6  Beta health damaging
2  Gamma  cigarettes per day                 Gamma
3  Delta         in his cave                 Delta

这里的掩码使用.str.contains 测试您的字符串是否存在，我们和条件一起制作掩码。