Условный подсчет частоты слов в Pandas

Question

У меня есть кадр данных, как показано ниже:

data = {'speaker':['Adam','Ben','Clair'],
        'speech': ['Thank you very much and good afternoon.',
                   'Let me clarify that because I want to make sure we have got everything right',
                   'By now you should have some good rest']}
df = pd.DataFrame(data)

Я хочу подсчитать количество слов в речевом столбце, но только для слов из предварительно определенного списка. Например, список:

wordlist = ['much', 'good','right']

Я хочу создать новый столбец, который показывает частоту этих трех слов в каждой строке. Таким образом, мой ожидаемый результат:

     speaker                   speech                               words
0   Adam          Thank you very much and good afternoon.             2
1   Ben        Let me clarify that because I want to make sur...      1
2   Clair        By now you should have received a copy of our ...    1

Я пытался:

df['total'] = 0
for word in df['speech'].str.split():
    if word in wordlist: 
        df['total'] += 1

Но после его запуска столбец total всегда равен нулю. Мне интересно, что не так с моим кодом?

Answer 1

Вы можете использовать следующий векторизованный подход:

data = {'speaker':['Adam','Ben','Clair'],
        'speech': ['Thank you very much and good afternoon.',
                   'Let me clarify that because I want to make sure we have got everything right',
                   'By now you should have some good rest']}
df = pd.DataFrame(data)

wordlist = ['much', 'good','right']

df['total'] = df['speech'].str.count(r'\b|\b'.join(wordlist))

, который дает:

>>> df
  speaker                                             speech  total
0    Adam            Thank you very much and good afternoon.      2
1     Ben  Let me clarify that because I want to make sur...      1
2   Clair              By now you should have some good rest      1

Answer 2

import pandas as pd

data = {'speaker': ['Adam', 'Ben', 'Clair'],
        'speech': ['Thank you very much and good afternoon.',
                   'Let me clarify that because I want to make sure we have got everything right',
                   'By now you should have some good rest']}
df = pd.DataFrame(data)

wordlist = ['much', 'good', 'right']

df["speech"] = df["speech"].str.split()
df = df.explode("speech")
counts = df[df.speech.isin(wordlist)].groupby("speaker").size()
print(counts)