如何在R语言中拆分dataframe的逗号分隔列并新增行

首先还原你提供的原始DataFrame：

df <- structure(list(tissue = c("thymus", "leg muscle", "liver", "stromal cell of bone marrow", 
"liver", "liver", "liver", "bone marrow", "skin", "balb/c"), 
    genotype = c("", "", "", "", "", "", "", "", "over-expressing PTN/OSF1,wild type genotype", 
    "")), row.names = c("S-4", "S-21", "S-25", "S-29", "S-47", "S-48", "S-49", "S-50", "S-61", "S-74"
), class = "data.frame")

要实现按逗号拆分genotype列、为每个拆分结果新增一行且保留对应tissue值的需求，用tidyr包的separate_rows()函数最便捷：

步骤1：准备依赖包 #

如果未安装过包含tidyr的tidyverse，先执行安装：

install.packages("tidyverse")

然后加载包：

library(tidyr)

步骤2：执行拆分操作 #

指定要拆分的列是genotype，分隔符为逗号，同时设置trim = TRUE自动去除拆分后字符串两端的空格：

df_split <- separate_rows(df, genotype, sep = ",", trim = TRUE)

处理后的核心结果 #

拆分后df_split的关键行如下：

#            tissue                        genotype
# S-4         thymus                                
# S-21   leg muscle                                
# ...
# S-61          skin over-expressing PTN/OSF1
# S-61.1        skin        wild type genotype
# S-74        balb/c                                

原S-61行的genotype被拆分为两行，对应的tissue值均保留为skin，其余空值行保持原样。

内容的提问来源于stack exchange，提问作者Nmgh