分组并在R中粘贴2个变量

我有一个data.frame，看起来像这样

df = data.frame(ticker = c(rep("AAPL", 2), rep("MSFT",2)), 
                Date = c("2019", "2017", "2017", "2016"))

print(df)

  ticker Date
1   AAPL 2019
2   AAPL 2017
3   MSFT 2017
4   MSFT 2016

我想按股票代码分组，并为每一行（日期）创建一个字符串。例如，我想创建两个如下所示的字符串

x = "SomeOtherString"

"SomeOtherStringAAPL20192017"

"SomeOtherStringMSFT20172016"

---

您可以对每个

ticker

使用

paste0

，如下所示：

library(dplyr)

df %>%
  group_by(ticker) %>%
  summarise(string = paste0(x, first(ticker), paste0(Date, collapse = '')))

#  ticker string                     
#  <chr>  <chr>                      
#1 AAPL   SomeOtherStringAAPL20192017
#2 MSFT   SomeOtherStringMSFT20172016

transform(aggregate(Date~ticker, df, paste0, collapse = ''), 
          string = paste0(x, ticker, Date))