如何结合两个因子向量以在R中创建一个？
为了合并两个因子向量，我们可以提取两个向量的唯一水平，然后合并这些水平。这可以通过使用独特的功能来完成。另外，我们可以将原始向量的水平设置为这些水平的组合，这样，我们就可以完成两个缺失水平的向量。查看以下示例以了解其工作原理。
例1
x1<−factor(LETTERS[1:5]) y1<−factor(LETTERS[1:7]) factor_levels1<−unique(c(levels(x1),levels(y1))) x1<−factor(x1,levels=factor_levels1) x1 [1] A B C D E Levels: A B C D E F G y1<−factor(y1,levels=factor_levels1) y1 [1] A B C D E F G Levels: A B C D E F G
例2
x2<−factor(LETTERS[1:26]) x2 [1] A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Levels: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z y2<−factor(LETTERS[11:26]) y2 [1] K L M N O P Q R S T U V W X Y Z Levels: K L M N O P Q R S T U V W X Y Z factor_levels2<−unique(c(levels(x2),levels(y2))) x2<−factor(x2,levels=factor_levels2) x2 [1] A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Levels: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z y2<−factor(y2,levels=factor_levels2) y2 [1] K L M N O P Q R S T U V W X Y Z Levels: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
范例3
x3<−factor(sample(c("India","China","Russia"),50,replace=TRUE))
x3
[1] Russia China India Russia India India India India China Russia
[11] China China China India India Russia India China Russia Russia
[21] China Russia Russia China India China India India China India
[31] India India India Russia India India Russia Russia China Russia
[41] Russia Russia India China Russia China India Russia China India
Levels: China India Russia
y3<−factor(sample(c("India","China","Russia","Indonesia","Croatia"),50,replace=TRUE))
y3
[1] Croatia China India Russia China India Indonesia
[8] China Indonesia Indonesia Russia India Indonesia Russia
[15] Croatia Croatia India Croatia Russia Russia India
[22] India Croatia Russia India China Croatia Russia
[29] India Russia China China Russia Russia India
[36] India India China Indonesia Indonesia Indonesia Indonesia
[43] China Croatia China Croatia Croatia India Indonesia
[50] Croatia
Levels: China Croatia India Indonesia Russia
factor_levels3<−unique(c(levels(x3),levels(y3)))
factor_levels3
[1] "China" "India" "Russia" "Croatia" "Indonesia"
x3<−factor(x3,levels=factor_levels3)
x3
[1] Russia China India Russia India India India India China Russia
[11] China China China India India Russia India China Russia Russia
[21] China Russia Russia China India China India India China India
[31] India India India Russia India India Russia Russia China Russia
[41] Russia Russia India China Russia China India Russia China India
Levels: China India Russia Croatia Indonesia
y3<−factor(y3,levels=factor_levels3)
y3
[1] Croatia China India Russia China India Indonesia
[8] China Indonesia Indonesia Russia India Indonesia Russia
[15] Croatia Croatia India Croatia Russia Russia India
[22] India Croatia Russia India China Croatia Russia
[29] India Russia China China Russia Russia India
[36] India India China Indonesia Indonesia Indonesia Indonesia
[43] China Croatia China Croatia Croatia India Indonesia
[50] Croatia
Levels: China India Russia Croatia Indonesia例子4
x4<−factor(sample(c("I","II"),50,replace=TRUE))
x4
[1] II I II I I I I II II II II I I II II II I I II I I I I II II
[26] II II II I II I I II I I I I II I I II I II I II I I I I I
Levels: I II
y4<−factor(sample(c("III","IV","V"),50,replace=TRUE))
y4
[1] V V V IV V III V V IV V III V IV III III III V V V
[20] V V IV III III V III III IV IV III III V V V III V V III
[39] IV III V IV III IV IV V IV IV V IV
Levels: III IV V
factor_levels4<−unique(c(levels(x4),levels(y4)))
factor_levels4
[1] "I" "II" "III" "IV" "V"
x4<−factor(x4,levels=factor_levels4)
x4
[1] II I II I I I I II II II II I I II II II I I II I I I I II II
[26] II II II I II I I II I I I I II I I II I II I II I I I I I
Levels: I II III IV V
y4<−factor(y4,levels=factor_levels4)
y4
[1] V V V IV V III V V IV V III V IV III III III V V V
[20] V V IV III III V III III IV IV III III V V V III V V III
[39] IV III V IV III IV IV V IV IV V IV
Levels: I II III IV V