如何将 R 数据框中的字符串转换为唯一整数？
要将R数据框中的字符串转换为唯一整数，我们首先需要提取数据框中的唯一字符串，然后data.frame使用as.numeric和因子函数在函数内部读取它们。
查看以下示例以了解其工作原理。
示例1
考虑以下数据框-
x1<-sample(c("Hot","Normal","Cold"),20,replace=TRUE)
x2<-sample(c("Hot","Normal","Cold"),20,replace=TRUE)
x3<-sample(c("Hot","Normal","Cold"),20,replace=TRUE)
df1<-data.frame(x1,x2,x3)
df1创建了以下数据框
x1 x2 x3 1 Hot Normal Hot 2 Hot Hot Normal 3 Hot Normal Hot 4 Hot Cold Normal 5 Hot Cold Hot 6 Hot Hot Cold 7 Hot Cold Cold 8 Normal Cold Cold 9 Hot Normal Cold 10 Hot Hot Hot 11 Normal Normal Hot 12 Normal Normal Normal 13 Hot Hot Cold 14 Normal Cold Cold 15 Hot Hot Hot 16 Cold Hot Normal 17 Hot Hot Hot 18 Hot Hot Cold 19 Hot Cold Cold 20 Cold Hot Hot
要在上述创建的数据框上提取数据框df1中的唯一值，请将以下代码添加到上述代码段中-
x1<-sample(c("Hot","Normal","Cold"),20,replace=TRUE)
x2<-sample(c("Hot","Normal","Cold"),20,replace=TRUE)
x3<-sample(c("Hot","Normal","Cold"),20,replace=TRUE)
df1<-data.frame(x1,x2,x3)
Unique_df1<-
unique(c(as.character(df1$x1),as.character(df1$x2),as.character(df1$x3)))
Unique_df1输出结果如果您将上述所有给定的片段作为单个程序执行，它会生成以下输出-
[1] "Hot" "Normal" "Cold"
要将df1中的字符串值转换为上面创建的数据框中的唯一数值，请将以下代码添加到上面的代码段中-
x1<-sample(c("Hot","Normal","Cold"),20,replace=TRUE)
x2<-sample(c("Hot","Normal","Cold"),20,replace=TRUE)
x3<-sample(c("Hot","Normal","Cold"),20,replace=TRUE)
df1<-data.frame(x1,x2,x3)
Unique_df1<-
unique(c(as.character(df1$x1),as.character(df1$x2),as.character(df1$x3)))
df1<-
data.frame(x1=as.numeric(factor(df1$x1,levels=Unique_df1)),x2=as.numeric(factor
(df1$x2,levels=Unique_df1)),x3=as.numeric(factor(df1$x3,levels=Unique_df1)))
df1输出结果如果您将上述所有给定的片段作为单个程序执行，它会生成以下输出-
x1 x2 x3 1 1 2 1 2 1 1 2 3 1 2 1 4 1 3 2 5 1 3 1 6 1 1 3 7 1 3 3 8 2 3 3 9 1 2 3 10 1 1 1 11 2 2 1 12 2 2 2 13 1 1 3 14 2 3 3 15 1 1 1 16 3 1 2 17 1 1 1 18 1 1 3 19 1 3 3 20 3 1 1
示例2
以下代码段创建了一个示例数据框-
y1<-sample(c("Summer","Rainy","Winter","Spring"),20,replace=TRUE)
y2<-sample(c("Summer","Rainy","Winter","Spring"),20,replace=TRUE)
y3<-sample(c("Summer","Rainy","Winter","Spring"),20,replace=TRUE)
df2<-data.frame(y1,y2,y3)
df2创建了以下数据框
y1 y2 y3 1 Rainy Winter Rainy 2 Summer Rainy Summer 3 Summer Spring Summer 4 Summer Spring Winter 5 Winter Winter Rainy 6 Summer Rainy Winter 7 Winter Winter Rainy 8 Winter Summer Spring 9 Spring Summer Winter 10 Summer Summer Spring 11 Rainy Rainy Spring 12 Rainy Winter Summer 13 Summer Spring Spring 14 Summer Summer Winter 15 Spring Spring Winter 16 Spring Spring Spring 17 Winter Spring Spring 18 Winter Rainy Summer 19 Winter Spring Winter 20 Winter Summer Summer
要在上述创建的数据框上提取数据框df2中的唯一值，请将以下代码添加到上述代码段中-
y1<-sample(c("Summer","Rainy","Winter","Spring"),20,replace=TRUE)
y2<-sample(c("Summer","Rainy","Winter","Spring"),20,replace=TRUE)
y3<-sample(c("Summer","Rainy","Winter","Spring"),20,replace=TRUE)
df2<-data.frame(y1,y2,y3)
Unique_df2<-
unique(c(as.character(df2$y1),as.character(df2$y2),as.character(df2$y3)))
Unique_df2输出结果如果您将上述所有给定的片段作为单个程序执行，它会生成以下输出-
[1] "Rainy" "Summer" "Winter" "Spring"
要将df2中的字符串值转换为上面创建的数据框中的唯一数值，请将以下代码添加到上面的代码段中-
y1<-sample(c("Summer","Rainy","Winter","Spring"),20,replace=TRUE)
y2<-sample(c("Summer","Rainy","Winter","Spring"),20,replace=TRUE)
y3<-sample(c("Summer","Rainy","Winter","Spring"),20,replace=TRUE)
df2<-data.frame(y1,y2,y3)
Unique_df2<-
unique(c(as.character(df2$y1),as.character(df2$y2),as.character(df2$y3)))
df2<-
data.frame(y1=as.numeric(factor(df2$y1,levels=Unique_df2)),y2=as.numeric(factor
(df2$y2,levels=Unique_df2)),y3=as.numeric(factor(df2$y3,levels=Unique_df2)))
df2输出结果如果您将上述所有给定的片段作为单个程序执行，它会生成以下输出-
y1 y2 y3 1 1 3 1 2 2 1 2 3 2 4 2 4 2 4 3 5 3 3 1 6 2 1 3 7 3 3 1 8 3 2 4 9 4 2 3 10 2 2 4 11 1 1 4 12 1 3 2 13 2 4 4 14 2 2 3 15 4 4 3 16 4 4 4 17 3 4 4 18 3 1 2 19 3 4 3 20 3 2 2