Combining rows with the same value into one column

[beginnersluke]

Hi everyone,

I'm fairly new to R, but so far it's proved a wonderful tool. I've had great luck finding the answers on how to do various tasks online, but now I'm stuck. I've read various instructionals for hours and have gotten no closer to solving my problem. I feel like this is an easy question, but I just can't get it; so I apologize.

Here is what I need to do. Imagine I have data with patients who have had their blood pressure taken. I have a long format dataset for this. So for example.

Name	Date	Systolic	Diastolic
John	1/1/10	132	92
Amy	1/2/10	120	80
John	2/2/10	135	92
Amy	2/2/10	82	118
Nick	2/14/10	108	72
Amy	3/1/10	122	80
John	3/3/10	128	88

Here is what I need:

Name	Date1	Systolic1	Diastolic1	Date2	Systolic2	Diastolic2	Date3	Systolic3	Diastolic3
John	1/1/10	132	92	2/2/10	135	92	3/3/10	128	88
Amy	1/2/10	120	80	2/2/10	82	118	3/1/10	122	80
Nick	2/14/10	108	72

I've tried all sorts of things with pivot_wider and group_by, but I've gotten nowhere.

I appreciate any help. Thanks SO much,

Luke

[mattwarkentin]

Hi @beginnersluke,

It is strongly recommended to keep your data as "long" for most tasks. It makes it much easier to plot, clean, etc.

However, since I don't know how you plan to use the data, here is a solution anyway:

library(tidyverse)
library(lubridate)

data <- 
tribble(
  ~Name, ~Date, ~Systolic, ~Diastolic,
  'John',   '1/1/10',   132,    92,
  'Amy',    '1/2/10',   120,    80,
  'John',   '2/2/10',   135,    92,
  'Amy',    '2/2/10',   82, 118,
  'Nick',   '2/14/10',  108,    72,
  'Amy',    '3/1/10',   122,    80,
  'John',   '3/3/10',   128,    88
)

data %>% 
  mutate(Date = mdy(Date)) %>% 
  arrange(Name, Date) %>% 
  group_by(Name) %>% 
  mutate(Visit = 1:n()) %>% 
  ungroup() %>% 
  pivot_wider(
    names_from = Visit, 
    values_from = c(Date, Systolic, Diastolic),
    names_sep = ''
  )
#> # A tibble: 3 x 10
#>   Name  Date1      Date2      Date3      Systolic1 Systolic2 Systolic3
#>   <chr> <date>     <date>     <date>         <dbl>     <dbl>     <dbl>
#> 1 Amy   2010-01-02 2010-02-02 2010-03-01       120        82       122
#> 2 John  2010-01-01 2010-02-02 2010-03-03       132       135       128
#> 3 Nick  2010-02-14 NA         NA               108        NA        NA
#> # … with 3 more variables: Diastolic1 <dbl>, Diastolic2 <dbl>, Diastolic3 <dbl>

^{Created on 2020-02-12 by the reprex package (v0.3.0)}