计算分数（从一等舱，二等舱和三等舱幸存的男性和女性乘客的分数

Question

我不确定如何完成家庭作业，在这里我必须根据男女所属的班级将其分组，以便找到每个班级中幸存的百分比。

这是所使用的文本文件中数据的一小部分。

1=alive
0=dead

Name                                            PClass Age  Sex     Survived

"Allen, Miss Elisabeth Walton"                  1st    29   female  1

"Allison, Miss Helen Loraine"                   1st     2   female  0

"Allison, Mr Hudson Joshua Creighton"           1st    30   male    0

"Allison, Mrs Hudson JC (Bessie Waldo Daniels)" 1st    25   female  0

"Allison, Master Hudson Trevor"                 1st    0.92 male    1

"Anderson, Mr Harry"                            1st    47   male    1

"Andrews, Miss Kornelia Theodosia"              1st    63   female  1

"Andrews, Mr Thomas, jr"                        1st    39   male    0

"Appleton, Mrs Edward Dale (Charlotte Lamson)"  1st    58   female  1

"Artagaveytia, Mr Ramon"                        1st    71   male    0

"Astor, Colonel John Jacob"                     1st    47   male    0

Answer 1

考虑使用dplyr库：

library(dplyr)

data %>%
  group_by(PClass, Sex) %>%
  summarize(ratio = sum(Survived) / n())

（未经验证的代码，对不起）

Answer 2

有多种方法可以做到这一点。假设DT是您的data.table，一种选择是使用聚合函数：

aggregate(DT$Survived, by=list(DT$PClass, DT$Sex)) 

看看documentation for aggregate来了解参数的含义。

另一种可能性是导入data.table库，然后按所需的列分组：

library(data.table)
DT[,list(mean_survival = mean(Survived)),by=.(PClass, Sex)]