如何在 R 中按列拆分数据框?
如果我们有一个数据框列包含一些重复值或表示类别,那么我们可能希望根据该列拆分数据框。
例如,如果我们有一个名为 df 的数据框,其中包含一个名为 Col 的列,那么我们可以使用下面给出的命令根据 Col 拆分数据框。
split(df,df$Col)
示例 1
以下代码片段创建了一个示例数据框。
Group<-sample(c("Male","Female"),20,replace=TRUE) Score<-rpois(20,8) df1<-data.frame(Group,Score) df1
创建了以下数据框:
Group Score 1 Male 8 2 Female 6 3 Female 5 4 Female 7 5 Female 12 6 Female 10 7 Female 9 8 Male 9 9 Male 10 10 Female 13 11 Female 4 12 Male 11 13 Female 5 14 Male 6 15 Female 9 16 Male 9 17 Female 5 18 Female 8 19 Male 3 20 Female 5
要根据 Group 列拆分 df1,请将以下代码添加到上述代码片段中:
Group<-sample(c("Male","Female"),20,replace=TRUE) Score<-rpois(20,8) df1<-data.frame(Group,Score) split(df1,df1$Group)
输出
如果将上述所有代码片段作为单个程序执行,则会生成以下输出:
$Female Group Score 2 Female 6 3 Female 5 4 Female 7 5 Female 12 6 Female 10 7 Female 9 10 Female 13 11 Female 4 13 Female 5 15 Female 9 17 Female 5 18 Female 8 20 Female 5 $Male Group Score 1 Male 8 8 Male 9 9 Male 10 12 Male 11 14 Male 6 16 Male 9 19 Male 3
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示例 2
以下代码片段创建了一个示例数据框。
Class<-sample(c("I","II","III"),20,replace=TRUE) Number_of_Customers<-sample(1:10,20,replace=TRUE) df2<-data.frame(Class,Number_of_Customers) df2
创建了以下数据框:
Class Number_of_Customers 1 II 2 2 I 10 3 III 2 4 III 4 5 III 5 6 III 7 7 III 10 8 II 4 9 II 9 10 I 7 11 III 4 12 I 1 13 I 1 14 I 1 15 III 5 16 II 5 17 II 9 18 II 8 19 II 8 20 I 9
要根据 Class 列拆分 df2,请将以下代码添加到上述代码片段中:
Class<-sample(c("I","II","III"),20,replace=TRUE) Number_of_Customers<-sample(1:10,20,replace=TRUE) df2<-data.frame(Class,Number_of_Customers) split(df2,df2$Class)
输出
如果将上述所有代码片段作为单个程序执行,则会生成以下输出:
$I Class Number_of_Customers 2 I 10 10 I 7 12 I 1 13 I 1 14 I 1 20 I 9 $II Class Number_of_Customers 1 II 2 8 II 4 9 II 9 16 II 5 17 II 9 18 II 8 19 II 8 $III Class Number_of_Customers 3 III 2 4 III 4 5 III 5 6 III 7 7 III 10 11 III 4 15 III 5
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