计算数据框中字符串的出现次数

Question

通过R，我可以很容易地从字符串列表中制作一个包含某些字符串模式频率的数据框。

library(stringr)
library(tm)
library(dplyr)    
text = c('i am so hhappy happy now','you look ssad','sad day today','noway')
dat = sapply(c('happy', 'sad'), function(i) str_count(text, i))
dat = data.frame(dat)  
dat = dat %>% mutate(Sentiment = (happy)-(sad))

结果，我可以有这样的数据框

  happy sad Sentiment
1     2   0         2
2     0   1        -1
3     0   1        -1
4     0   0         0

在 Python 中，我可以假设除 sapply() 之外的其余代码

import pandas as pd
text = ['i am so hhappy happy now','you look ssad','sad day today','noway']
????
dat = pd.DataFrame(dat)
dat['Sentiment'] = dat.apply(lambda c: c.happy - c.sad)

???? 会是什么？

Answer 1

你可以使用pd.Series.str.count:

import pandas as pd
import numpy as np

text = ['i am so hhappy happy now','you look ssad','sad day today','noway']
df = pd.DataFrame({'text' : text})

df['happy'] = df.text.str.count('happy')
df['sad'] = df.text.str.count('sad')
df['Sentiment'] = df.happy - df.sad

df    
                      text  happy  sad  Sentiment
0  i am so happy happy now      2    0          2
1             you look sad      0    1         -1
2            sad day today      0    1         -1
3                    noway      0    0          0