Summarize data at different aggregate levels - R and tidyverse - r

I'm creating a bunch of basic status reports and one of things I'm finding tedious is adding a total row to all my tables. I'm currently using the Tidyverse approach and this is an example of my current code. What I'm looking for is an option to have a few different levels included by default.
#load into RStudio viewer (not required)
iris = iris
#summary at the group level
summary_grouped = iris %>%
group_by(Species) %>%
summarize(mean_s_length = mean(Sepal.Length),
max_s_width = max(Sepal.Width))
#summary at the overall level
summary_overall = iris %>%
summarize(mean_s_length = mean(Sepal.Length),
max_s_width = max(Sepal.Width)) %>%
mutate(Species = "Overall")
#append results for report
summary_table = rbind(summary_grouped, summary_overall)
Doing this multiple times over is very tedious. I kind of want:
summary_overall = iris %>%
group_by(Species, total = TRUE) %>%
summarize(mean_s_length = mean(Sepal.Length),
max_s_width = max(Sepal.Width))
FYI - if you're familiar with SAS I'm looking for the same type of functionality available via a class, ways or types statements in proc means that let me control the level of summarization and get multiple levels in one call.
Any help is appreciated. I know I can create my own function, but was hoping there is something that already exists. I would also prefer to stick with the tidyverse style of programming though I'm not set on that.

Another alternative:
library(tidyverse)
iris %>%
mutate_at("Species", as.character) %>%
list(group_by(.,Species), .) %>%
map(~summarize(.,mean_s_length = mean(Sepal.Length),
max_s_width = max(Sepal.Width))) %>%
bind_rows() %>%
replace_na(list(Species="Overall"))
#> # A tibble: 4 x 3
#> Species mean_s_length max_s_width
#> <chr> <dbl> <dbl>
#> 1 setosa 5.01 4.4
#> 2 versicolor 5.94 3.4
#> 3 virginica 6.59 3.8
#> 4 Overall 5.84 4.4

You can write a function which does the same summarize on an ungrouped tibble and rbinds that to the end.
summarize2 <- function(df, ...){
bind_rows(summarise(df, ...), summarize(ungroup(df), ...))
}
iris %>%
group_by(Species) %>%
summarize2(
mean_s_length = mean(Sepal.Length),
max_s_width = max(Sepal.Width)
)
# # A tibble: 4 x 3
# Species mean_s_length max_s_width
# <fct> <dbl> <dbl>
# 1 setosa 5.01 4.4
# 2 versicolor 5.94 3.4
# 3 virginica 6.59 3.8
# 4 NA 5.84 4.4
You could add some logic for what the "Overall" groups should be named if you want
summarize2 <- function(df, ...){
s1 <- summarise(df, ...)
s2 <- summarize(ungroup(df), ...)
for(v in group_vars(s1)){
if(is.factor(s1[[v]]))
s1[[v]] <- as.character(s1[[v]])
if(is.character(s1[[v]]))
s2[[v]] <- 'Overall'
else if(is.numeric(s1[[v]]))
s2[[v]] <- -Inf
}
bind_rows(s1, s2)
}
iris %>%
group_by(Species, g = Petal.Length %/% 1) %>%
summarize2(
mean_s_length = mean(Sepal.Length),
max_s_width = max(Sepal.Width)
)
# # Groups: Species [4]
# Species g mean_s_length max_s_width
# <chr> <dbl> <dbl> <dbl>
# 1 setosa 1 5.01 4.4
# 2 versicolor 3 5.35 2.9
# 3 versicolor 4 6.09 3.4
# 4 versicolor 5 6.35 3
# 5 virginica 4 5.85 3
# 6 virginica 5 6.44 3.4
# 7 virginica 6 7.43 3.8
# 8 Overall -Inf 5.84 4.4

library(dplyr)
iris %>%
group_by(Species) %>%
summarize(mean_s_length = mean(Sepal.Length),
max_s_width = max(Sepal.Width)) %>%
ungroup() %>%
mutate_at(vars(Species), as.character) %>%
{rbind(.,c("Overal",mean(.$mean_s_length),max(.$max_s_width)))} %>%
mutate_at(vars(-Species), as.double) %>%
mutate_at(vars(Species), as.factor)
#> # A tibble: 4 x 3
#> Species mean_s_length max_s_width
#> <fct> <dbl> <dbl>
#> 1 setosa 5.01 4.4
#> 2 versicolor 5.94 3.4
#> 3 virginica 6.59 3.8
#> 4 Overal 5.84 4.4
Created on 2019-06-21 by the reprex package (v0.3.0)

One way, also tedious but in one longer pipe, is to put the second summarise instructions in bind_rows.
The as.character call avoids a warning:
Warning messages:
1: In bind_rows_(x, .id) :
binding factor and character vector, coercing into character vector
2: In bind_rows_(x, .id) :
binding character and factor vector, coercing into character vector
library(tidyverse)
summary_grouped <- iris %>%
mutate(Species = as.character(Species)) %>%
group_by(Species) %>%
summarize(mean_s_length = mean(Sepal.Length),
max_s_width = max(Sepal.Width)) %>%
bind_rows(iris %>%
summarize(mean_s_length = mean(Sepal.Length),
max_s_width = max(Sepal.Width)) %>%
mutate(Species = "Overall"))
## A tibble: 4 x 3
# Species mean_s_length max_s_width
# <chr> <dbl> <dbl>
#1 setosa 5.01 4.4
#2 versicolor 5.94 3.4
#3 virginica 6.59 3.8
#4 Overall 5.84 4.4

Maybe something like this:
As you want to perform different operations on the same input (iris), best to map over the different summary functions and apply to the data.
map_dfr combines the list outputs using bind_rows
library(dplyr)
library(purrr)
pipe <- . %>%
group_by(Species) %>%
summarize(
mean_s_length = mean(Sepal.Length),
max_s_width = max(Sepal.Width))
map_dfr(
list(pipe, . %>% mutate(Species = "Overall") %>% pipe),
exec,
iris)
#> Warning in bind_rows_(x, .id): binding factor and character vector,
#> coercing into character vector
#> Warning in bind_rows_(x, .id): binding character and factor vector,
#> coercing into character vector
#> # A tibble: 4 x 3
#> Species mean_s_length max_s_width
#> <chr> <dbl> <dbl>
#> 1 setosa 5.01 4.4
#> 2 versicolor 5.94 3.4
#> 3 virginica 6.59 3.8
#> 4 Overall 5.84 4.4

Solution where you need to apply wanted function only once on a double dataset:
library(tidyverse)
iris %>%
rbind(mutate(., Species = "Overall")) %>%
group_by(Species) %>%
summarize(
mean_s_length = mean(Sepal.Length),
max_s_width = max(Sepal.Width)
)
# A tibble: 4 x 3
Species mean_s_length max_s_width
<chr> <dbl> <dbl>
1 Overall 5.84 4.4
2 setosa 5.01 4.4
3 versicolor 5.94 3.4
4 virginica 6.59 3.8
Trick is to pass original dataset with a new group ID (ie Species): mutate(iris, Species = "Overall")

Related

dplyr group_by - Mix variable names with and without surrounding quotes

I'd like to be able to use dplyr's group_by to group by multiple columns, simple enough. But, the complication is I want to create a function where one or more columns are always in the group by and the user can select an additional column to group by. What I've tried so far involves using the non-string specification of the columns that are always in the group by and using a string for the column the user selects, but nothing I've tried works. This combination seems to work fine in SELECT, but not GROUP_BY. Ideally, I'd rather not switch to all strings because I want to be able to take advantage of some of the functionality of dplyr that allows me to select a range of columns. Below is an example.
To make a simple example, I started with the iris data set and added a couple more columns, their exact meanings are not important.
test_tbl <- iris %>%
mutate(extra_var1 = ifelse(Sepal.Length >= 5.0, "Yes", "No"),
extra_var2 = "What")
Here's an example that uses the non-string specification for all variables, which works just fine:
test_tbl %>%
select(Species, extra_var1, Sepal.Length, Petal.Width) %>%
group_by(Species, extra_var1) %>%
summarize(average.Sepal.Length = mean(Sepal.Length),
average.Petal.Width = mean(Petal.Width))
But, I'd like to be able to, within a function, have the user specify whether they want to group by extra_var1 or extra_var2. Here's my attempt, which doesn't work. Again, I believe the select part works fine, but the group_by part does not.
group_and_summarize <- function(var) {
test_tbl %>%
select(Species, var, Sepal.Length, Petal.Width) %>%
group_by(Species, var) %>%
summarize(average.Sepal.Length = mean(Sepal.Length),
average.Petal.Width = mean(Petal.Width))
}
group_and_summarize("extra_var1")
This would be one way to do it:
library(dplyr)
group_and_summarize <- function(var) {
test_tbl %>%
select(Species, {{var}}, Sepal.Length, Petal.Width) %>%
group_by(Species, {{var}}) %>%
summarize(average.Sepal.Length = mean(Sepal.Length),
average.Petal.Width = mean(Petal.Width))
}
group_and_summarize(extra_var1)
#> `summarise()` regrouping output by 'Species' (override with `.groups` argument)
#> # A tibble: 6 x 4
#> # Groups: Species [3]
#> Species extra_var1 average.Sepal.Length average.Petal.Width
#> <fct> <chr> <dbl> <dbl>
#> 1 setosa No 4.67 0.195
#> 2 setosa Yes 5.23 0.28
#> 3 versicolor No 4.9 1
#> 4 versicolor Yes 5.96 1.33
#> 5 virginica No 4.9 1.7
#> 6 virginica Yes 6.62 2.03
Created on 2021-05-11 by the reprex package (v0.3.0)
If you want the user to enter strings then we can use !!! syms():
group_and_summarize <- function(vars) {
test_tbl %>%
select(Species, !!! syms(vars), Sepal.Length, Petal.Width) %>%
group_by(Species, !!! syms(vars)) %>%
summarize(average.Sepal.Length = mean(Sepal.Length),
average.Petal.Width = mean(Petal.Width))
}
group_and_summarize(c("extra_var1", "extra_var2"))
#> `summarise()` regrouping output by 'Species', 'extra_var1' (override with `.groups` argument)
#> # A tibble: 6 x 5
#> # Groups: Species, extra_var1 [6]
#> Species extra_var1 extra_var2 average.Sepal.Length average.Petal.Width
#> <fct> <chr> <chr> <dbl> <dbl>
#> 1 setosa No What 4.67 0.195
#> 2 setosa Yes What 5.23 0.28
#> 3 versicolor No What 4.9 1
#> 4 versicolor Yes What 5.96 1.33
#> 5 virginica No What 4.9 1.7
#> 6 virginica Yes What 6.62 2.03
Created on 2021-05-11 by the reprex package (v0.3.0)

Group t test result into columns within tidyverse

I'd like to group multiple t test result into one table. Originally my code looks like this:
tt_data <- iris %>%
group_by(Species) %>%
summarise(p = t.test(Sepal.Length,Petal.Length,alternative="two.sided",paired=T)$p.value,
estimate = t.test(Sepal.Length,Petal.Length,alternative="two.sided",paired=T)$estimate
)
tt_data
# Species p estimate
# setosa 2.542887e-51 3.544
# versicolor 9.667914e-36 1.676
# virginica 7.985259e-28 1.036
However, base on the idea that I should only perform the statistical test once, is there a way for me to run t test once per group and collect the intended table? I think there are some combination of broom and purrr but I am unfamiliar with the syntax.
# code idea (I know this won't work!)
tt_data <- iris %>%
group_by(Species) %>%
summarise(tt = t.test(Sepal.Length,Petal.Length,alternative="two.sided",paired=T)) %>%
select(Species, tt.p, tt.estimate)
tt_data
# Species tt.p tt.estimate
# setosa 2.542887e-51 3.544
# versicolor 9.667914e-36 1.676
# virginica 7.985259e-28 1.036
You can use broom::tidy() to transform the resut of the t.test to a tidy 'tibble':
library(dplyr)
library(broom)
iris %>%
group_by(Species) %>%
group_modify(~{
t.test(.$Sepal.Length,.$Petal.Length,alternative="two.sided",paired=T) %>%
tidy()
}) %>%
select(estimate, p.value)
#> Adding missing grouping variables: `Species`
#> # A tibble: 3 x 3
#> # Groups: Species [3]
#> Species estimate p.value
#> <fct> <dbl> <dbl>
#> 1 setosa 3.54 2.54e-51
#> 2 versicolor 1.68 9.67e-36
#> 3 virginica 1.04 7.99e-28
Created on 2020-09-02 by the reprex package (v0.3.0)
You can use map to select the desired values from the list generated by t.test and by tidying it up to a data frame via broom::tidy, i.e.
library(dplyr)
iris %>%
group_by(Species) %>%
summarise(p = list(broom::tidy(t.test(Sepal.Length, Petal.Length, alternative = "two.sided", paired = T)))) %>%
mutate(p.value = purrr::map(p, ~select(.x, c('p.value', 'estimate')))) %>%
select(-p) %>%
unnest()
# A tibble: 3 x 3
# Species p.value estimate
# <fct> <dbl> <dbl>
#1 setosa 2.54e-51 3.54
#2 versicolor 9.67e-36 1.68
#3 virginica 7.99e-28 1.04

R Dplyr: Summarizing a column, if it is present

In R, working in the tidyverse:
My data sources change. There's a column which is only present some weeks. When it is, I want to summarize it. Using iris as an example, suppose that Sepal.Width is sometimes missing. Conceptually, I want a function like this
library(tidyverse)
summIris <- function(irisDf){
irisDf %>%
group_by(Species) %>%
summarise_ifPresent(
Sepal.Length = mean(Sepal.Length),
Sepal.Width = mean(Sepal.Width))
}
Which'd return
R > summIris(iris )
# A tibble: 3 x 3
Species Sepal.Length Sepal.Width
<fct> <dbl> <dbl>
1 setosa 5.01 3.43
2 versicolor 5.94 2.77
3 virginica 6.59 2.97
> summIris(iris %>% select(- Sepal.Width ))
# A tibble: 3 x 2
Species Sepal.Length
<fct> <dbl>
1 setosa 5.01
2 versicolor 5.94
3 virginica 6.59
I could work around by wrapping the logic in if else. But is there something more concise and elegant?
summarize_at allows you to define on which columns you execute the summary, and you can use starts_with, ends_with, matches, or contains to dynamically select columns.
library(dplyr)
iris %>%
group_by(Species) %>%
summarize_at(vars(starts_with("Sepal")), funs(mean(.)))
# # A tibble: 3 x 3
# Species Sepal.Length Sepal.Width
# <fct> <dbl> <dbl>
# 1 setosa 5.01 3.43
# 2 versicolor 5.94 2.77
# 3 virginica 6.59 2.97
iris %>%
select(-Sepal.Length) %>%
group_by(Species) %>%
summarize_at(vars(starts_with("Sepal")), funs(mean(.)))
# # A tibble: 3 x 2
# Species Sepal.Width
# <fct> <dbl>
# 1 setosa 3.43
# 2 versicolor 2.77
# 3 virginica 2.97
Another one also works but gives a warning with unfound columns:
iris %>%
select(-Sepal.Length) %>%
group_by(Species) %>%
summarize_at(vars(one_of(c("Sepal.Width", "Sepal.Length"))), funs(mean(.)))
# Warning: Unknown columns: `Sepal.Length`
# # A tibble: 3 x 2
# Species Sepal.Width
# <fct> <dbl>
# 1 setosa 3.43
# 2 versicolor 2.77
# 3 virginica 2.97

R dplyr: Write list output to dataframe

Suppose I have the following function
SlowFunction = function(vector){
return(list(
mean =mean(vector),
sd = sd(vector)
))
}
And I would like to use dplyr:summarise to write the results to a dataframe:
iris %>%
dplyr::group_by(Species) %>%
dplyr::summarise(
mean = SlowFunction(Sepal.Length)$mean,
sd = SlowFunction(Sepal.Length)$sd
)
Does anyone have a suggestion how I can do this by calling "SlowFunction" once instead of twice? (In my code "SlowFunction" is a slow function that I have to call many times.) Without splitting "SlowFunction" in two parts of course. So actually I would like to somehow fill multiple columns of a dataframe in one statement.
Without changing your current SlowFunction one way is to use do
library(dplyr)
iris %>%
group_by(Species) %>%
do(data.frame(SlowFunction(.$Sepal.Length)))
# Species mean sd
# <fct> <dbl> <dbl>
#1 setosa 5.01 0.352
#2 versicolor 5.94 0.516
#3 virginica 6.59 0.636
Or with group_split + purrr::map_dfr
bind_cols(Species = unique(iris$Species), iris %>%
group_split(Species) %>%
map_dfr(~SlowFunction(.$Sepal.Length)))
An option is to use to store the output of SlowFunction in a list column of data.frames and then to use unnest
iris %>%
group_by(Species) %>%
summarise(res = list(as.data.frame(SlowFunction(Sepal.Length)))) %>%
unnest()
## A tibble: 3 x 3
# Species mean sd
# <fct> <dbl> <dbl>
#1 setosa 5.01 0.352
#2 versicolor 5.94 0.516
#3 virginica 6.59 0.636
We can use group_map if you are using dplyr 0.8.0 or later. The output from SlowFunction needs to be converted to a data frame.
library(dplyr)
iris %>%
group_by(Species) %>%
group_map(~SlowFunction(.x$Sepal.Length) %>% as.data.frame())
# # A tibble: 3 x 3
# # Groups: Species [3]
# Species mean sd
# <fct> <dbl> <dbl>
# 1 setosa 5.01 0.352
# 2 versicolor 5.94 0.516
# 3 virginica 6.59 0.636
We can change the SlowFunction to return a tibble and
SlowFunction = function(vector){
tibble(
mean =mean(vector),
sd = sd(vector)
)
}
and then unnest the summarise output in a list
iris %>%
group_by(Species) %>%
summarise(out = list(SlowFunction(Sepal.Length))) %>%
unnest
# A tibble: 3 x 3
# Species mean sd
# <fct> <dbl> <dbl>
#1 setosa 5.01 0.352
#2 versicolor 5.94 0.516
#3 virginica 6.59 0.636

How does one summarize with conditions into a single variable in R?

I would like to use summarise() from dplyr after grouping data to compute a new variable. But, I would like it to use one equation for some of the data and a second equation for the rest of the data.
I have tried using group_by() and and summarise() with if_else() but it isn't working.
Here's an example. Let's say--for some reason--I wanted to find a special value for sepal length. For the species 'setosa' this special value is twice the mean of the sepal length. For all of the other species it is simply the mean of sepal length. This is the code I've tried, but it doesn't work with summarise()
library(dplyr)
iris %>%
group_by(Species) %>%
summarise(sepal_special = if_else(Species == "setosa", mean(Sepal.Length)*2, mean(Sepal.Length)))
This idea works with mutate() but I would need to re-format the tibble to be the dataset I am looking for.
library(dplyr)
iris %>%
group_by(Species) %>%
mutate(sepal_special = if_else(Species == "setosa", mean(Sepal.Length)*2, mean(Sepal.Length)))
This is how I want the resulting tibble to be laid out:
library(dplyr)
iris %>%
group_by(Species)%>%
summarise(sepal_mean = mean(Sepal.Length))
# A tibble: 3 x 2
# Species sepal_special
# <fctr> <dbl>
#1 setosa 5.01
#2 versicolor 5.94
#3 virginica 6.59
#>
But my result would show the value for setosa x 2
# A tibble: 3 x 2
# Species sepal_special
# <fctr> <dbl>
#1 setosa **10.02**
#2 versicolor 5.94
#3 virginica 6.59
#>
Suggestions? I feel like I've really searched for ways to use if_else() with summarise() but can't find it anywhere, which means there must be a better way.
Thanks!
After the mutate step, use summarise to get the first element of 'sepal_special' for each 'Species'
iris %>%
group_by(Species) %>%
mutate(sepal_special = if_else(Species == "setosa",
mean(Sepal.Length)*2, mean(Sepal.Length))) %>%
summarise(sepal_special = first(sepal_special))
# A tibble: 3 x 2
# Species sepal_special
# <fctr> <dbl>
#1 setosa 10.0
#2 versicolor 5.94
#3 virginica 6.59
Or instead of calling the mutate, after the if_else is applied, get the first value in summarise
iris %>%
group_by(Species) %>%
summarise(sepal_special = if_else(Species == "setosa",
mean(Sepal.Length)*2, mean(Sepal.Length))[1])
# A tibble: 3 x 2
# Species sepal_special
# <fctr> <dbl>
#1 setosa 10.0
#2 versicolor 5.94
#3 virginica 6.59
Another option: since twice the mean is the same as the mean of twice the values, you can double the sepal lengths for setosa and then summarise:
iris %>%
mutate(Sepal.Length = ifelse(Species == "setosa", 2*Sepal.Length, Sepal.Length)) %>%
group_by(Species) %>%
summarise(sepal_special = mean(Sepal.Length))
# A tibble: 3 x 2
Species sepal_special
<fct> <dbl>
1 setosa 10.0
2 versicolor 5.94
3 virginica 6.59

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