计算数据框中字符串的出现次数

Question

通过R，我可以轻松地创建一个数据帧，其中包含来自字符串列表的某些字符串模式的频率。

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，我可以有一个这样的数据框

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

在Python中，我可以假设其余代码 sapply()

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)

那会????是什么？

Answer 1

您可以使用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