[R] Avoid duplication in dplyr::summarise

[Edjabou Vincent]

Hi Lars

I am not very sure what you really want. However, I am suggesting the
following code that enables (1) to obtain the full summary of your data and
(2) retrieve only mean of X values as function of factors f1 and f2.

library(tidyverse)
library(psych)
df <- data.frame(matrix(rnorm(40), 10, 4),
                 f1 = gl(3, 10, labels = letters[1:3]),
                 f2 = gl(3, 10, labels = letters[4:6]))

##To get all summary of your data
df%>% gather(X_name,X_value,X1:X4)%>%
  group_by(f1,f2,X_name)%>%
  do(describe(.$X_value))

##To obtain only means of your data
df%>% gather(X_name,X_value,X1:X4)%>%
  group_by(f1,f2,X_name)%>%
  do(describe(.$X_value))%>%
  select(mean)%>%# You select only mean value
  spread(X_name,mean)#

Vincent

Med venlig hilsen/ Best regards

Edjabou Maklawe Essonanawe Vincent
Mobile: +45 31 95 99 33

On Sat, Sep 9, 2017 at 12:30 PM, Lars Bishop <lars52r at gmail.com> wrote:

> Dear group,
>
> Is there a way I could avoid the sort of duplication illustrated below?
> i.e., I have the same dplyr::summarise function on different group_by
> arguments. So I'd like to create a single summarise function that could be
> applied to both. My attempt below fails.
>
> df <- data.frame(matrix(rnorm(40), 10, 4),
>                  f1 = gl(3, 10, labels = letters[1:3]),
>                  f2 = gl(3, 10, labels = letters[4:6]))
>
>
> df %>%
>   group_by(f1, f2) %>%
>   summarise(x1m = mean(X1),
>             x2m = mean(X2),
>             x3m = mean(X3),
>             x4m = mean(X4))
>
> df %>%
>   group_by(f1) %>%
>   summarise(x1m = mean(X1),
>             x2m = mean(X2),
>             x3m = mean(X3),
>             x4m = mean(X4))
>
> # My fail attempt
>
> s <- function() {
>   dplyr::summarise(x1m = mean(X1),
>                    x2m = mean(X2),
>                    x3m = mean(X3),
>                    x4m = mean(X4))
> }
>
> df %>%
>   group_by(f1) %>% s
> Error in s(.) : unused argument (.)
>
> Regards,
> Lars.
>
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>
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