Q:

How can concatenate all values in a new object while grouping via Object B

I'm trying to manipulate some raw data into a more meaningful output.  I'm looking to concatenate values in column B based on Column A.
For example 
Col A   Col B  
user1   action1
user1   action2
user1   action3
user1   action4
user2   action10
user3   action4
user4   action5
user4   action1

Into something like 
User1  action1 > action2 > action3 > action4
User2  action10 
User3  action4
User4  action5 > action1

A:

This should do it:
library(dplyr)

data %>% 
     group_by(Col_A) %>% 
     summarize(Col_B = paste0(Col_B, collapse = " > ")) 

