Tabyl: A Frequency Desk for the Fashionable R Person | by Zvonimir Boban | Might, 2023

Out with the previous, in with the brand new!

Anybody who has labored with categorical knowledge ultimately got here throughout a have to calculate absolutely the quantity and proportion of a sure class. This text introduces the tabyl operate for creating frequency tables by a sequence of hands-on examples.

What does tabyl deliver to the desk (no pun supposed :D)?

The tabyl operate is a function of the janitor package deal in R. It’s a really handy instrument for creating contingency tables, in any other case often called frequency tables or cross-tabulations. Listed below are a number of the advantages of utilizing tabyl:

1. Simple syntax: tabyl has an easy-to-use syntax. It will possibly take one, two, or three variables, and it robotically returns a knowledge body that features counts and proportions.

2. Flexibility: tabyl can generate one-way (single variable), two-way (two variables), and three-way (three variables) contingency tables. This flexibility makes it appropriate for a variety of functions.

3. Computerized calculation of proportions: tabyl robotically calculates the proportions (percentages) for one-way contingency tables. For 2 and three-way tables, the identical end result could be achieved together with the adorn_percentages operate from the identical package deal.

4. Compatibility with dplyr: The output of tabyl is a knowledge body (or tibble), which makes it totally suitable with dply capabilities and the tidyverse ecosystem. This implies you possibly can simply pipe %>% the output into additional knowledge wrangling or visualization capabilities.

5. Neat and informative output: tabyl offers neat and informative output, which incorporates the variable names as row names and column names, making it simpler to interpret the outcomes.

For all these causes, tabyl is a superb alternative if you need to create frequency tables in R. It simplifies many steps and integrates properly with the tidyverse strategy to knowledge evaluation.

The dataset

This submit will exhibit the advantages of the tabyl operate from the janitor package deal utilizing the information on the edibility of various kinds of mushrooms relying on their odor. Right here, I might be utilizing a tidied dataset beneath the identify mushrooms, however you possibly can entry the original data on Kaggle. Under is the code used for cleansing the information.

library(tidyverse)
library(janitor)
mushrooms <- read_csv("mushrooms.csv") %>%
choose(class, odor) %>%
mutate(
class = case_when(
class == "p" ~ "toxic",
class == "e" ~ "edible"
),
odor = case_when(
odor == "a" ~ "almond",
odor == "l" ~ "anise",
odor == "c" ~ "creosote",
odor == "y" ~ "fishy",
odor == "f" ~ "foul",
odor == "m" ~ "musty",
odor == "n" ~ "none",
odor == "p" ~ "pungent",
odor == "s" ~ "spicy"
)
)

If you’re unfamiliar with the above syntax, please take a look at a hands-on information to utilizing the tidyverse in one in all my earlier articles.

The previous

To be able to higher perceive which benefits tabyl provides, let’s first make a frequency desk utilizing the bottom R desk operate.

desk(mushrooms$class)
edible toxic 
4208      3916 

desk(mushrooms$odor, mushrooms$class)
edible toxic
almond      400         0
anise       400         0
creosote      0       192
fishy         0       576
foul          0      2160
musty         0        36
none       3408       120
pungent       0       256
spicy         0       576

Unsurprisingly, it seems that odor is a superb predictor of mushroom edibility, with something “funny-smelling” in all probability being toxic. Thanks evolution! Additionally, there appear to be many extra toxic mushrooms, so it’s all the time vital to be cautious when selecting mushrooms by yourself.

If we would like to have the ability to use the variable names straight with out specifying the $ operator, we would wish to make use of the with command to make the dataset obtainable to the desk operate.

mush_table <- with(mushrooms, desk(odor, class))

Sadly, if we need to improve to proportions as a substitute of absolute numbers, we cannot use the identical operate however one other one as a substitute — prop.desk .

prop.desk(mush_table)
class
odor            edible   toxic
almond   0.049236829 0.000000000
anise    0.049236829 0.000000000
creosote 0.000000000 0.023633678
fishy    0.000000000 0.070901034
foul     0.000000000 0.265878877
musty    0.000000000 0.004431315
none     0.419497784 0.014771049
pungent  0.000000000 0.031511571
spicy    0.000000000 0.070901034

By default, this offers us a column-wise proportion desk. If we would like row-wise proportions, we are able to specify the margin argument (1 for row-wise and a pair of for column-wise).

prop.desk(mush_table, margin = 1)
class
odor           edible  toxic
almond   1.00000000 0.00000000
anise    1.00000000 0.00000000
creosote 0.00000000 1.00000000
fishy    0.00000000 1.00000000
foul     0.00000000 1.00000000
musty    0.00000000 1.00000000
none     0.96598639 0.03401361
pungent  0.00000000 1.00000000
spicy    0.00000000 1.00000000

All these particular capabilities can really feel cumbersome and arduous to recollect, so a single operate which accommodates all of the above funcionality could be good to have.

Moreover, if we test the kind of the created object utilizing the class(mush_table) command, we see that it’s of a category desk.

This creates a compatibility downside, since these days R customers are principally utilizing the tidyverse ecosystem which is centered round making use of capabilities to knowledge.body sort objects and stringing the outcomes collectively utilizing the pipe (%>%) operator.

The brand new

Let’s do the identical issues with the tabyl operate.

tabyl(mushrooms, class)
class    n   p.c
edible 4208 0.5179714
toxic 3916 0.4820286

mush_tabyl <- tabyl(mushrooms, odor, class)
mush_tabyl
odor edible toxic
almond    400         0
anise    400         0
creosote      0       192
fishy      0       576
foul      0      2160
musty      0        36
none   3408       120
pungent      0       256
spicy      0       576

In comparison with the corresponding desk output, the ensuing tables aretidier utilizing the tabyl operate, with variable names (class) being explicitly acknowledged. Furthermore, for the one-way desk, except for numbers, the chances are robotically generated as properly.

We will additionally discover that we didn’t have to make use of the which functio to have the ability to specify the variable names straight. Moreover, operating class(mush_tabyl) tells us that the ensuing object is of a knowledge.body class which ensures tidyverse compatibility!

The adorned janitor

For added tabyl functionalities, the janitor package deal additionally accommodates a sequence of adorn capabilities. To get the chances, we merely pipe the ensuing frequency desk to the adorn_percentages operate.

mush_tabyl %>% adorn_percentages()
odor    edible  toxic
almond 1.0000000 0.00000000
anise 1.0000000 0.00000000
creosote 0.0000000 1.00000000
fishy 0.0000000 1.00000000
foul 0.0000000 1.00000000
musty 0.0000000 1.00000000
none 0.9659864 0.03401361
pungent 0.0000000 1.00000000
spicy 0.0000000 1.00000000

If we would like the column-wise percentages, we are able to specify the denominator argument as “col”.

mush_tabyl %>% adorn_percentages(denominator = "col")
odor     edible   toxic
almond 0.09505703 0.000000000
anise 0.09505703 0.000000000
creosote 0.00000000 0.049029622
fishy 0.00000000 0.147088866
foul 0.00000000 0.551583248
musty 0.00000000 0.009193054
none 0.80988593 0.030643514
pungent 0.00000000 0.065372829
spicy 0.00000000 0.147088866

The tabyl — adorn combo even permits us to simply mix each the quantity and proportion in a similar desk cell…

mush_tabyl %>% adorn_percentages %>% adorn_ns
odor           edible         toxic
almond 1.0000000  (400) 0.00000000    (0)
anise 1.0000000  (400) 0.00000000    (0)
creosote 0.0000000    (0) 1.00000000  (192)
fishy 0.0000000    (0) 1.00000000  (576)
foul 0.0000000    (0) 1.00000000 (2160)
musty 0.0000000    (0) 1.00000000   (36)
none 0.9659864 (3408) 0.03401361  (120)
pungent 0.0000000    (0) 1.00000000  (256)
spicy 0.0000000    (0) 1.00000000  (576)

… or add the totals to the rows and columns.

mush_tabyl %>% adorn_totals(c("row", "col"))
odor edible toxic Whole
almond    400         0   400
anise    400         0   400
creosote      0       192   192
fishy      0       576   576
foul      0      2160  2160
musty      0        36    36
none   3408       120  3528
pungent      0       256   256
spicy      0       576   576
Whole   4208      3916  8124

Conclusion

The tabyl() operate from the janitor package deal in R provides a user-friendly and versatile resolution for creating one-way, two-way, or three-way contingency tables. It excels in robotically computing proportions and producing tidy knowledge frames that combine seamlessly with the tidyverse ecosystem, particularly dplyr. Its outputs are well-structured and straightforward to interpret, and it may be additional enhanced with adorn capabilities, simplifying the general strategy of producing informative frequency tables. This makes tabyl() a extremely useful instrument in knowledge evaluation in R.