将函数应用于pandas dataframe列

时间:2017-12-19 01:03:16

标签: python pandas dataframe apply

我有一个关于电影的用户评论的数据框,并且想要解析用户何时将电影描述为" movie1"遇见" movie2"

User id     Old id_New id   Score   Comments
947952018   3101_771355141  3.0 If you want to see a comedy and have a stupid ...
805407067   11903_18330     5.0 Argento?s fever dream masterpiece. Fairy tale ...
901306244   16077_771225176 4.5 Evil Dead II meets Brothers Grimm and Hawkeye ...
901306244   NaN_381422014   1.0 Biggest disappointment! There's a host of ...
15169683    NaN_22471       3.0 You know in the original story of Pinocchio he...

我写了一个收录评论的功能,发现单词" meet"并且在会面之前和之后取前n个单词并且返回(希望)movie1&的标题的本质。 movie2,我计划稍后模糊匹配另一个数据帧中的标题。

def parse_movie(comment, num_words):
    words = comment.partition('meets')
    words_before = words[0].split(maxsplit=num_words)[-num_words:] 
    words_after = words[2].split(maxsplit=num_words)[:num_words]
    movie1 = ' '.join(words_before)
    movie2 = ' '.join(words_after)
    return movie1, movie2

如何在原始pandas数据框的comments列中应用此函数,并将返回的movie1和movie2标题放在不同的列中?我试过了

df['Comments'].apply(parse_titles) 

但是我不能指定我想要使用的num_words。直接在列上操作对我来说也不起作用,我不知道如何将新电影放入新列。

parse_movie(sample['Comments'], 4)
AttributeError: 'Series' object has no attribute 'partition'

建议将不胜感激!

1 个答案:

答案 0 :(得分:1)

基于how to split column of tuples in pandas dataframe?回答。这可以使用lambda函数和apply(pd.Series)来完成。将结果保存到dataframe列' movie1'和' movie2'。

num_words = 4
df[['movie1','movie2']] = df['comments'].apply(lambda comment: parse_movie(comment, num_words)).apply(pd.Series)