问题
I am not able to figure out how to get r to correctly show the head of my data. This is an assignment for Swirl, so I have to figure out how to write my code in a way that Swirl will accept as the answer.
Swirl wants the final printout to look exactly like this:
## Pclass agecat Sex N survivors perc_survived
## <int> <fctr> <chr> <int> <int> <dbl>
## 1 Under 15 female 2 1 50.000000
## 1 Under 15 male 3 3 100.000000
## 1 15 to 50 female 70 68 97.142857
## 1 15 to 50 male 72 32 44.444444
## 1 Over 50 female 13 13 100.000000
## 1 Over 50 male 26 5 19.230769
#
My code:
library(dplyr)
titanic_4 <- titanic %>%
select(Survived, Pclass, Age, Sex) %>%
filter(!is.na(Age)) %>%
mutate(agecat = cut(Age, breaks = c(0, 14.99, 50, 150),
include.lowest = TRUE,
labels = c("Under 15", "15 to 50",
"Over 50"))) %>%
group_by(Pclass,agecat,Sex) %>%
summarize(N=n(), survivors = sum(Survived))%>%
mutate(perc_survived = (signif((100*survivors/N), digits=8)))
print(titanic_4)
Gives:
# A tibble: 18 x 6
# Groups: Pclass, agecat [9]
Pclass agecat Sex N survivors perc_survived
<int> <fctr> <chr> <int> <int> <dbl>
1 1 Under 15 female 2 1 50.000000
2 1 Under 15 male 3 3 100.000000
3 1 15 to 50 female 70 68 97.142857
4 1 15 to 50 male 72 32 44.444444
5 1 Over 50 female 13 13 100.000000
6 1 Over 50 male 26 5 19.230769
7 2 Under 15 female 10 10 100.000000
8 2 Under 15 male 9 9 100.000000
9 2 15 to 50 female 61 56 91.803279
10 2 15 to 50 male 78 5 6.410256
11 2 Over 50 female 3 2 66.666667
12 2 Over 50 male 12 1 8.333333
13 3 Under 15 female 27 13 48.148148
14 3 Under 15 male 27 9 33.333333
15 3 15 to 50 female 74 33 44.594595
16 3 15 to 50 male 217 29 13.364055
17 3 Over 50 female 1 1 100.000000
18 3 Over 50 male 9 0 0.000000
When I head(titanic_4), r rounds the data in the last column (perc_survivied):
# A tibble: 6 x 6
# Groups: Pclass, agecat [3]
Pclass agecat Sex N survivors perc_survived
<int> <fctr> <chr> <int> <int> <dbl>
1 1 Under 15 female 2 1 50.00000
2 1 Under 15 male 3 3 100.00000
3 1 15 to 50 female 70 68 97.14286
4 1 15 to 50 male 72 32 44.44444
5 1 Over 50 female 13 13 100.00000
6 1 Over 50 male 26 5 19.23077
However, I would like R to give me six decimal places in perc_survived so that it will look like this:
## Pclass agecat Sex N survivors perc_survived
## <int> <fctr> <chr> <int> <int> <dbl>
## 1 Under 15 female 2 1 50.000000
## 1 Under 15 male 3 3 100.000000
## 1 15 to 50 female 70 68 97.142857
## 1 15 to 50 male 72 32 44.444444
## 1 Over 50 female 13 13 100.000000
## 1 Over 50 male 26 5 19.230769
Can anyone tell me how to tell r to keep 6 decimal place? Thank you so much!
From Comments:
*Maybe print(titanic[1:6,])? – Florian
I tried the method proposed by Florian, but it did not change the rounding results
> titanic_4 <- titanic %>%
+ select(Survived, Pclass, Age, Sex) %>%
+ filter(!is.na(Age)) %>%
+ mutate(agecat = cut(Age, breaks = c(0, 14.99, 50, 150),
+ include.lowest = TRUE,
+ labels = c("Under 15", "15 to 50",
+ "Over 50"))) %>%
+ group_by(Pclass,agecat,Sex) %>%
+ summarize(N=n(), survivors = sum(Survived))%>%
+ mutate(perc_survived = (signif((100*survivors/N), digits=8)))
>
> print(titanic_4[1:6,])
# A tibble: 6 x 6
# Groups: Pclass, agecat [3]
Pclass agecat Sex N survivors perc_survived
<int> <fctr> <chr> <int> <int> <dbl>
1 1 Under 15 female 2 1 50.00000
2 1 Under 15 male 3 3 100.00000
3 1 15 to 50 female 70 68 97.14286
4 1 15 to 50 male 72 32 44.44444
5 1 Over 50 female 13 13 100.00000
6 1 Over 50 male 26 5 19.23077
>
With regards to the Answer by Eric Fail, sprintf causes the column to change to character. This is an assignment for Swirl(), and swirl will not accept the type change.
> titanic_4 <- titanic %>%
+ select(Survived, Pclass, Age, Sex) %>%
+ filter(!is.na(Age)) %>%
+ mutate(agecat = cut(Age, breaks = c(0, 14.99, 50, 150),
+ include.lowest = TRUE,
+ labels = c("Under 15", "15 to 50",
+ "Over 50"))) %>%
+ group_by(Pclass,agecat,Sex) %>%
+ summarize(N=n(), survivors = sum(Survived))%>%
+ mutate(perc_survived = sprintf("%0.6f",(signif((100*survivors/N), digits=8))))
>
> head (titanic_4)
# A tibble: 6 x 6
# Groups: Pclass, agecat [3]
Pclass agecat Sex N survivors perc_survived
<int> <fctr> <chr> <int> <int> <chr>
1 1 Under 15 female 2 1 50.000000
2 1 Under 15 male 3 3 100.000000
3 1 15 to 50 female 70 68 97.142857
4 1 15 to 50 male 72 32 44.444444
5 1 Over 50 female 13 13 100.000000
6 1 Over 50 male 26 5 19.230769
The suggestion to use option(digits=8) was successful. In order to get this suggestion to work, before running my code, I had to change the basic options of r so that it would round to the right number of digits. My r was set to round to 5.
> options(digits=8)
> titanic_4 <- titanic %>%
+ select(Survived, Pclass, Age, Sex) %>%
+ filter(!is.na(Age)) %>%
+ mutate(agecat = cut(Age, breaks = c(0, 14.99, 50, 150),
+ include.lowest = TRUE,
+ labels = c("Under 15", "15 to 50",
+ "Over 50"))) %>%
+ group_by(Pclass,agecat,Sex) %>%
+ summarize(N=n(), survivors = sum(Survived))%>%
+ mutate(perc_survived = (round((100*survivors/N),digits=6)))
>
> head (titanic_4)
# A tibble: 6 x 6
# Groups: Pclass, agecat [3]
Pclass agecat Sex N survivors perc_survived
<int> <fctr> <chr> <int> <int> <dbl>
1 1 Under 15 female 2 1 50.000000
2 1 Under 15 male 3 3 100.000000
3 1 15 to 50 female 70 68 97.142857
4 1 15 to 50 male 72 32 44.444444
5 1 Over 50 female 13 13 100.000000
6 1 Over 50 male 26 5 19.230769
Thank you very much for your comments and answers. Best wishes,
Drew
回答1:
sprintf(c(.8693683839, .7869698963), fmt='%#.6g')
#> [1] "0.869368" "0.786970"
and specifically for your case,
titanic_4 <- tibble(perc_survived = c(50.000000, 100.000000, 97.142857,
44.444444, 100.000000, 19.230769))
titanic_4
#> # A tibble: 6 x 1
#> perc_survived
#> <dbl>
#> 1 50.00000
#> 2 100.00000
#> 3 97.14286
#> 4 44.44444
#> 5 100.00000
#> 6 19.23077
#> >
>
titanic_4 <- titanic_4 %>% mutate(perc_survived_6 = sprintf("%0.6f", perc_survived))
titanic_4
#> # A tibble: 6 x 2
#> perc_survived perc_survived_6
#> <dbl> <chr>
#> 1 50.00000 50.000000
#> 2 100.00000 100.000000
#> 3 97.14286 97.142857
#> 4 44.44444 44.444444
#> 5 100.00000 100.000000
#> 6 19.23077 19.230769
or possible changing the global digits,
options(digits=8)
titanic_4
#> # A tibble: 6 x 1
#> perc_survived
#> <dbl>
#> 1 50.000000
#> 2 100.000000
#> 3 97.142857
#> 4 44.444444
#> 5 100.000000
#> 6 19.230769
回答2:
The answer to this question was given by Eric Fail on this page.
Changing the Global Digits options of the console using options(digits=8) solved the rounding problems in the head(). For a list of Global Options, visit this website. https://stat.ethz.ch/R-manual/R-devel/library/base/html/options.html
I had also created another post which showed how my console was rounding. G5W showed me how to fix the problem by adjusting the global digits.
How can I tell R to round correctly?
By default, the global digits in my r studio were set too low for me to correctly use round() or signf(). I needed to set the digits to 8 to achieve the correct rounding.
Thank you Eric Fail and G5W
来源：https://stackoverflow.com/questions/48357595/r-rounding-when-head-data