我有一个列，其观察结果为字符类型，并按如下方式组织(输出示例如下):
df <- data.frame(observation = c('["Extra pillows and blankets", "Dishes and silverware", "Room-darkening shades", "Hot water kettle", "Ethernet connection", "Wifi", "Dedicated workspace", "Oven"]',
'["Extra pillows and blankets", "Dishes and silverware", "Room-darkening shades", "Hot water kettle", "Ethernet connection", "Wifi", "Dedicated workspace", "Oven"]',
'["Extra pillows and blankets", "Dishes and silverware", "Room-darkening shades", "Hot water kettle", "Ethernet connection", "Wifi", "Dedicated workspace", "Oven"]'
))
我的目标是计算每个观察的每个列表中的元素数量(考虑在列表中用逗号分隔这些元素)。 我尝试过将其转换为一个因子、一个列表，我使用了长度和长度，以及许多其他我什至不记得的东西。有谁知道如何解决这个问题吗？
最佳答案
我们可以使用str_count()对元素进行计数:
这里我们对进行计数，并加1来得到元素的数量:
library(dplyr)
library(stringr)
df %>%
mutate(n_elements = str_count(observation, ",")+1)
1 ["Extra pillows and blankets", "Dishes and silverware", "Room-darkening shades", "Hot water kettle", "Ethernet connection", "Wifi", "Dedicated workspace", "Oven"]
2 ["Extra pillows and blankets", "Dishes and silverware", "Room-darkening shades", "Hot water kettle", "Ethernet connection", "Wifi", "Dedicated workspace", "Oven"]
3 ["Extra pillows and blankets", "Dishes and silverware", "Room-darkening shades", "Hot water kettle", "Ethernet connection", "Wifi", "Dedicated workspace", "Oven"]
n_elements
1 8
2 8
3 8
关于r - 计算列表中的值，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/76190404/