在r中折叠同一作者的每4个连续文本行

Question

我想将作者的每四篇文章合并到一个广泛的数据框中，如果剩下的文章少于四篇，则将这些合并（例如，作者有 11 篇文章，我最终得到 2 篇 4 篇文章和 1 篇文章3)。

这是我的数据框的示例：

name  text
bee   _ so we know that right           
bee   said so           
alma  hello,            
alma  Good to hear back from you.           
bee   I've currently written an application         
alma  I'm happy about it            
bee   It was not the last.          
alma  Will this ever stop.          
alma  Yet another line.         
alma  so            

我想改成这样：

name  text
bee   _ so we know that right said so I've currently written an application It was not the last.
alma  hello, Good to hear back from you. I'm happy about it Will this ever stop
alma  Yet another line. so

这是初始数据框：

df = structure(list(name = c("bee", "bee", "alma", "alma", "bee", "alma", "bee", "alma", "alma", "alma"), text = c( "_ so we know that right", "said so", "hello,", "Good to hear back from you.", "I've currently written an application", "I'm happy about it", "It was not the last.", "Will this ever stop.", "Yet another line.", "so")), .Names = c("name", "text"), row.names = c(NA, -10L), class = "data.frame")

Answer 1

使用dplyr 的一个选项可能是：

df %>%
 group_by(name) %>%
 mutate(ID = ceiling(row_number()/4)) %>%
 group_by(name, ID) %>%
 summarise_all(paste, collapse = " ")

  name     ID text                                                                         
  <chr> <dbl> <chr>                                                                        
1 alma      1 hello, Good to hear back from you. I'm happy about it Will this ever stop.   
2 alma      2 Yet another line. so                                                         
3 bee       1 _ so we know that right said so I've currently written an application It was…