有时每行需要区别对待,因此,我们可能希望将这些行转换为列表。这将帮助我们分别对行元素执行操作。要将行转换为列表,我们可以通过定义数据框中的行数来使用拆分功能。
请看以下数据帧-
set.seed(101) x1<-rnorm(20,5,1) x2<-rnorm(20,5,2) x3<-rnorm(20,5,1.5) x4<-rnorm(20,3,0.096) df1<-data.frame(x1,x2,x3,x4) df1
输出结果
x1 x2 x3 x4 1 4.673964 4.672489 5.723688 2.975059 2 5.552462 6.417044 6.137321 2.864527 3 4.325056 4.464039 1.521009 2.938430 4 5.214359 2.072156 4.310743 3.010796 5 5.310769 6.488872 3.341924 3.040570 6 6.173966 2.179220 5.604392 3.037136 7 5.618790 5.934135 5.853402 2.933971 8 4.887266 4.761360 3.940875 3.014295 9 5.917028 5.934478 4.564864 2.994466 10 4.776741 5.996271 2.774183 2.992817 11 5.526448 6.789874 3.274617 3.144950 12 4.205156 5.558304 4.588293 3.155514 13 6.427756 7.015732 5.866852 3.110703 14 3.533180 0.853787 2.904646 2.992550 15 4.763317 7.379707 6.123587 2.825382 16 4.806662 3.551252 3.423220 2.900405 17 4.150245 5.335968 5.248071 3.029039 18 5.058465 6.840670 6.694714 2.877317 19 4.182330 1.656790 6.760584 3.013281 20 2.949692 5.896938 4.358205 2.995106
将df1的行转换为列表-
df1_row_list <-split(df1,1:nrow(df1))
df1_row_list
$`1`
x1 x2 x3 x4 1 4.673964 4.672489 5.723688 2.975059
$`2`
x1 x2 x3 x4 2 5.552462 6.417044 6.137321 2.864527
$`3`
x1 x2 x3 x4 3 4.325056 4.464039 1.521009 2.93843
$`4`
x1 x2 x3 x4 4 5.214359 2.072156 4.310743 3.010796
$`5`
x1 x2 x3 x4 5 5.310769 6.488872 3.341924 3.04057
$`6`
x1 x2 x3 x4 6 6.173966 2.17922 5.604392 3.037136
$`7`
x1 x2 x3 x4 7 5.61879 5.934135 5.853402 2.933971
$`8`
x1 x2 x3 x4 8 4.887266 4.76136 3.940875 3.014295
$`9`
x1 x2 x3 x4 9 5.917028 5.934478 4.564864 2.994466
$`10`
x1 x2 x3 x4 10 4.776741 5.996271 2.774183 2.992817
$`11`
x1 x2 x3 x4 11 5.526448 6.789874 3.274617 3.14495
$`12`
x1 x2 x3 x4 12 4.205156 5.558304 4.588293 3.155514
$`13`
x1 x2 x3 x4 13 6.427756 7.015732 5.866852 3.110703
$`14`
x1 x2 x3 x4 14 3.53318 0.853787 2.904646 2.99255
$`15`
x1 x2 x3 x4 15 4.763317 7.379707 6.123587 2.825382
$`16`
x1 x2 x3 x4 16 4.806662 3.551252 3.42322 2.900405
$`17`
x1 x2 x3 x4 17 4.150245 5.335968 5.248071 3.029039
$`18`
x1 x2 x3 x4 18 5.058465 6.84067 6.694714 2.877317
$`19`
x1 x2 x3 x4 19 4.18233 1.65679 6.760584 3.013281
$`20`
x1 x2 x3 x4 20 2.949692 5.896938 4.358205 2.995106
is.list(df1_row_list) [1] TRUE
让我们看另一个例子-
y1<-LETTERS[1:20] y2<-1:20 y3<-sample(0:9,20,replace=TRUE) y4<-rpois(20,3) y5<-rexp(20,3) df2<-data.frame(y1,y2,y3,y4,y5) df2
输出结果
y1 y2 y3 y4 y5 1 A 1 6 1 0.12535201 2 B 2 1 4 0.04849127 3 C 3 7 4 0.10894953 4 D 4 0 4 0.32620261 5 E 5 3 7 0.04711375 6 F 6 5 2 0.10263975 7 G 7 3 1 0.35080088 8 H 8 2 4 0.25617221 9 I 9 0 0 0.31124956 10 J 10 0 5 0.07771391 11 K 11 7 2 0.02583599 12 L 12 2 2 0.06699178 13 M 13 3 3 0.04767600 14 N 14 1 4 0.11942077 15 O 15 6 4 0.62873345 16 P 16 3 6 0.08066371 17 Q 17 3 3 0.58563662 18 R 18 9 0 0.00548393 19 S 19 0 2 0.01171107 20 T 20 0 1 0.10728116
将df2的行转换为列表-
df2_row_list <-split(df2,1:nrow(df2))
df2_row_list
$`1`
y1 y2 y3 y4 y5 1 A 1 4 2 0.02331396
$`2`
y1 y2 y3 y4 y5 2 B 2 6 2 0.2343971
$`3`
y1 y2 y3 y4 y5 3 C 3 1 5 0.022928
$`4`
y1 y2 y3 y4 y5 4 D 4 3 2 0.009332871
$`5`
y1 y2 y3 y4 y5 5 E 5 3 4 0.3321631
$`6`
y1 y2 y3 y4 y5 6 F 6 8 5 0.6256276
$`7`
y1 y2 y3 y4 y5 7 G 7 8 2 0.03358184
$`8`
y1 y2 y3 y4 y5 8 H 8 2 3 0.2089223
$`9`
y1 y2 y3 y4 y5 9 I 9 6 3 0.5231238
$`10`
y1 y2 y3 y4 y5 10 J 10 7 3 0.01456478
$`11`
y1 y2 y3 y4 y5 11 K 11 2 2 0.670605
$`12`
y1 y2 y3 y4 y5 12 L 12 1 2 0.1021066
$`13`
y1 y2 y3 y4 y5 13 M 13 5 7 0.2673457
$`14`
y1 y2 y3 y4 y5 14 N 14 0 1 0.442615
$`15`
y1 y2 y3 y4 y5 15 O 15 3 5 0.2244831
$`16`
y1 y2 y3 y4 y5 16 P 16 7 2 0.2897614
$`17`
y1 y2 y3 y4 y5 17 Q 17 2 4 0.4671283
$`18`
y1 y2 y3 y4 y5 18 R 18 7 3 0.274696
$`19`
y1 y2 y3 y4 y5 19 S 19 0 2 0.1120801
$`20`
y1 y2 y3 y4 y5 20 T 20 8 5 0.2727685
is.list(df2_row_list)[1]是