计算字符串中逗号分隔的唯一值 [英] Count comma separated unique values in a string

问题描述

数据帧的前两列构成一个复合键，有一列 char 类型包含逗号分隔的整数.我的目标是制作一列，其中包含字符串中唯一整数的计数.我知道使用 str_split_fixed 将字符串转换为列然后计算唯一值的方法，但是由于字符串的长度，添加了大量列并且一切都滞后.有没有其他方法?实际数据集包含 500k 行和 53 列.示例数据集:
df

The first two columns of dataframe make a composite key and there's a column of type char which contains comma separated integers. My objective is to make a column which contains the count of unique integers in the string. I know the approach of converting string to columns using str_split_fixed and then counting the unique values but due to the length of string a large number of columns are added and everything lags. Is there any other method? The actual data set contains 500k rows and 53 columns. Sample dataset :
df

c1      c2    c3  
aa      11   1,13,4,5,4,7,9    
bb      22   2,5,2,4,5,7,11,     
cc      33   11,14,3,1,    
dd      44   1,1,2,4,5,6,15,    
ee      55   4,3,3,1,14,17,

期望的输出:

c1        c2             c3             c4  
------ | ------   | ------          | -----   
aa     | 11       | 1,13,4,5,4,7,9  |  6    
------ | ------   | ------          | -----   
bb     | 22       | 2,5,2,4,5,7,11, |  5   
------ | ------   | ------          | -----   
cc     | 33       | 11,14,3,1,      |  4   
------ | ------   | ------          | -----   
dd     | 44       | 1,1,2,4,5,6,15, |  6       
------ | ------   | ------          | -----   
ee     | 55       | 4,3,3,1,7,17,7, |  5    
------ | ------   | ------          | -----  

任何帮助将不胜感激！

推荐答案

我们可以使用 stri_extract 来提取所有的数字，然后遍历list，找到<unique 元素的代码>长度

We can use stri_extract to extract all the numbers, then loop through the list, find the length of unique elements

library(stringi)
df1$Count <- sapply(stri_extract_all_regex(df1$col3, "[0-9]+"), 
                     function(x) length(unique(x)))

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