R语言中如何隐藏数据框显示时的自动行号？

我有如下数据框：

table_a = structure(list(elephant = c(1L, 1L, 1L, 1L, 2L, 2L, 2L, 3L, 4L, 
4L, 5L, 5L), elephant_status = c("performing", "performing", 
"performing", "performing", "performing", "performing", "performing", 
"performing", "performing", "performing", "performing", "performing"
), year = c(2015L, 2016L, 2017L, 2018L, 2018L, 2019L, 2020L, 
2015L, 2018L, 2019L, 2016L, 2021L), year_escaped = c("2018", 
"2018", "2018", "2018", "2022", "2022", "2022", "2015", "NULL", 
"NULL", "NULL", "NULL")), class = "data.frame", row.names = c(NA, 
-12L))

查看数据框时，左侧会显示自动生成的行号：

elephant elephant_status year year_escaped
1         1      performing 2015         2018
2         1      performing 2016         2018
3         1      performing 2017         2018
4         1      performing 2018         2018
5         2      performing 2018         2022
6         2      performing 2019         2022
7         2      performing 2020         2022
8         3      performing 2015         2015
9         4      performing 2018         NULL
10        4      performing 2019         NULL
11        5      performing 2016         NULL
12        5      performing 2021         NULL

我尝试过rownames(table_a) = NULL，但显示时左侧行号仍然存在，请问如何编写R代码让显示数据框时不显示这些行号？

有几种不同的方法可以实现显示数据框时隐藏行号，根据使用场景选择：

1. 基础R的print()函数控制 #

直接使用print()函数并设置row.names = FALSE参数，就能在显示时隐藏行号：

print(table_a, row.names = FALSE)

输出效果：

elephant elephant_status year year_escaped
        1      performing 2015         2018
        1      performing 2016         2018
        1      performing 2017         2018
        1      performing 2018         2018
        2      performing 2018         2022
        2      performing 2019         2022
        2      performing 2020         2022
        3      performing 2015         2015
        4      performing 2018         NULL
        4      performing 2019         NULL
        5      performing 2016         NULL
        5      performing 2021         NULL

2. 转为tibble格式（推荐） #

tibble是tidyverse生态中的数据结构，默认显示时不包含传统行号，格式更清晰。先安装并加载tibble包，然后转换数据框：

# 首次使用时安装包
install.packages("tibble")
# 加载包并转换
library(tibble)
table_a_tbl <- as_tibble(table_a)
# 直接查看即可
table_a_tbl

输出效果类似：

# A tibble: 12 × 4
   elephant elephant_status  year year_escaped
      <int> <chr>           <int> <chr>       
 1        1 performing       2015 2018        
 2        1 performing       2016 2018        
 3        1 performing       2017 2018        
 4        1 performing       2018 2018        
 5        2 performing       2018 2022        
 6        2 performing       2019 2022        
 7        2 performing       2020 2022        
 8        3 performing       2015 2015        
 9        4 performing       2018 NULL        
10        4 performing       2019 NULL        
11        5 performing       2016 NULL        
12        5 performing       2021 NULL        

这里的数字是tibble的行索引标记，并非传统行号，且大数据集只会显示部分行，更实用。

3. 在R Markdown中使用knitr::kable() #

如果是在R Markdown文档中输出表格，使用knitr包的kable()函数，设置row.names = FALSE即可隐藏行号：

library(knitr)
kable(table_a, row.names = FALSE)

输出的表格不会包含行号，适合生成报告类文档。

内容的提问来源于stack exchange，提问作者stats_noob