如何将 R 数据框中的字符串转换为唯一整数?
r programmingserver side programmingprogramming更新于 2025/4/11 19:07:17
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，然后使用 as.numeric 和 factor 函数在 data.frame 函数中读取它们。
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
要提取上面创建的数据框中数据框 df1 中的唯一值，请将以下代码添加到上面的代码片段中 −
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$x3)))
Unique_df1
输出
如果将上述所有代码片段作为一个程序执行，则会生成以下输出 −
[1] "Hot" "Normal" "Cold"
要将 df1 中的字符串值转换为上述创建的数据框中的唯一数值，请将以下代码添加到上述代码片段中 −
x1<-sample(c("Hot","Normal","Cold"),20,replace=TRUE)
x2<-sample(c("Hot","Normal","Cold"),20,replace=TRUE)
x3<-sample(c("Hot","Normal","Cold"),20,replace=TRUE)
df1<-data.frame(x1,x2,x3)
Unique_df1<-
unique(c(as.character(df1$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$x3,levels=Unique_df1)))
df1
输出
如果将上述所有代码片段作为一个程序执行，则会生成以下输出 −
x1 x2 x3 1 1 2 1 2 1 1 2 3 1 2 1 4 1 3 2 5 1 3 1 6 1 1 3 7 1 3 3 8 2 3 3 9 1 2 3 10 1 1 1 11 2 2 1 12 2 2 2 13 1 1 3 14 2 3 3 15 1 1 1 16 3 1 2 17 1 1 1 18 1 1 3 19 1 3 3 20 3 1 1
示例 2
以下代码片段创建了一个示例数据框 −
y1<-sample(c("Summer","Rainy","Winter","Spring"),20,replace=TRUE)
y2<-sample(c("Summer","Rainy","Winter","Spring"),20,replace=TRUE)
y3<-sample(c("Summer","Rainy","Winter","Spring"),20,replace=TRUE)
df2<-data.frame(y1,y2,y3)
df2
创建以下数据框
y1 y2 y3
1 Rainy Winter Rainy
2 Summer Rainy Summer
3 Summer Spring Summer
4 Summer Spring Winter
5 Winter Winter Rainy
6 Summer Rainy Winter
7 Winter Winter Rainy
8 Winter Summer Spring
9 Spring Summer Winter
10 Summer Summer Spring
11 Rainy Rainy Spring
12 Rainy Winter Summer
13 Summer Spring Spring
14 Summer Summer Winter
15 Spring Spring Winter
16 Spring Spring Spring
17 Winter Spring Spring
18 Winter Rainy Summer
19 Winter Spring Winter
20 Winter Summer Summer
要提取上面创建的数据框中数据框 df2 中的唯一值，请将以下代码添加到上面的代码片段中 −
y1<-sample(c("Summer","Rainy","Winter","Spring"),20,replace=TRUE)
y2<-sample(c("Summer","Rainy","Winter","Spring"),20,replace=TRUE)
y3<-sample(c("Summer","Rainy","Winter","Spring"),20,replace=TRUE)
df2<-data.frame(y1,y2,y3)
Unique_df2<-
unique(c(as.character(df2$y1),as.character(df2$y2),as.character(df2$y3)))
Unique_df2
输出
如果将上述所有代码片段作为一个程序执行，则会生成以下输出 −
[1] "Rainy" "Summer" "Winter" "Spring"
要将 df2 中的字符串值转换为上述创建的数据框中的唯一数值，请将以下代码添加到上述代码片段中 −
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
如果将上述所有代码片段作为一个程序执行，则会生成以下输出 −
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
