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法学如何将R数据框的列转换为单个向量？
有时数据框中的所有列都具有相似的數據特征，代表一个特定的变量。例如，有一个数据框包含五列，每列都是人们的身高。要将此类型的数据框转换为向量，我们可以使用as.vector函数以及as.matrix函数。as.matrix将读取数据框列，以便可以创建值数组。
示例1
考虑以下数据框：
set.seed(101) x1<−rnorm(20) x2<−rnorm(20) x3<−rnorm(20,5,0.34) df1<−data.frame(x1,x2,x3) df1
输出
x1 x2 x3 1 −0.3260365 −0.1637557 5.164036 2 0.5524619 0.7085221 5.257793 3 −0.6749438 −0.2679805 4.211429 4 0.2143595 −1.4639218 4.843768 5 0.3107692 0.7444358 4.624170 6 1.1739663 −1.4103902 5.136996 7 0.6187899 0.4670676 5.193438 8 −0.1127343 −0.1193201 4.759932 9 0.9170283 0.4672390 4.901369 10 −0.2232594 0.4981356 4.495481 11 0.5264481 0.8949372 4.608913 12 −0.7948444 0.2791520 4.906680 13 1.4277555 1.0078658 5.196486 14 −1.4668197 −2.0731065 4.525053 15 −0.2366834 1.1898534 5.254680 16 −0.1933380 −0.7243742 4.642597 17 −0.8497547 0.1679838 5.056229 18 0.0584655 0.9203352 5.384135 19 −0.8176704 −1.6716048 5.399066 20 −2.0503078 0.4484691 4.854527
将df1转换为向量：
示例
df1_vector<−as.vector(as.matrix(df1[,c("x1","x2","x3")]))
df1_vector输出
[1] −0.3260365 0.5524619 −0.6749438 0.2143595 0.3107692 1.1739663 [7] 0.6187899 −0.1127343 0.9170283 −0.2232594 0.5264481 −0.7948444 [13] 1.4277555 −1.4668197 −0.2366834 −0.1933380 −0.8497547 0.0584655 [19] −0.8176704 −2.0503078 −0.1637557 0.7085221 −0.2679805 −1.4639218 [25] 0.7444358 −1.4103902 0.4670676 −0.1193201 0.4672390 0.4981356 [31] 0.8949372 0.2791520 1.0078658 −2.0731065 1.1898534 −0.7243742 [37] 0.1679838 0.9203352 −1.6716048 0.4484691 5.1640360 5.2577927 [43] 4.2114287 4.8437684 4.6241696 5.1369956 5.1934379 4.7599317 [49] 4.9013692 4.4954815 4.6089132 4.9066798 5.1964863 4.5250531 [55] 5.2546796 4.6425965 5.0562295 5.3841351 5.3990656 4.8545265
示例2
y1<−sample(LETTERS[1:26],20) y2<−sample(LETTERS[1:26],20) y3<−sample(LETTERS[1:26],20) y4<−sample(LETTERS[1:26],20) df2<−data.frame(y1,y2,y3,y4) df2
输出
y1 y2 y3 y4 1 G V P Y 2 A J N A 3 E L X L 4 K E B O 5 P Z O E 6 W T T Z 7 X N J U 8 L D L J 9 U U Z X 10 Y B A F 11 F M W I 12 Q P F B 13 T Y H M 14 H C K T 15 I F Y W 16 N G G H 17 R A M K 18 S K E G 19 C O U Q 20 O W D V
将df2转换为向量：
示例
df2_vector<−as.vector(as.matrix(df2[,c("y1","y2","y3","y4")]))
df2_vector输出
[1] "G" "A" "E" "K" "P" "W" "X" "L" "U" "Y" "F" "Q" "T" "H" "I" "N" "R" "S" "C" [20] "O" "V" "J" "L" "E" "Z" "T" "N" "D" "U" "B" "M" "P" "Y" "C" "F" "G" "A" "K" [39] "O" "W" "P" "N" "X" "B" "O" "T" "J" "L" "Z" "A" "W" "F" "H" "K" "Y" "G" "M" [58] "E" "U" "D" "Y" "A" "L" "O" "E" "Z" "U" "J" "X" "F" "I" "B" "M" "T" "W" "H" [77] "K" "G" "Q" "V"
更新于：2021年2月8日
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