如何使用 dplyr 将 R 中单列 data.table 对象的第一个字母转换为大写?
r programmingserver side programmingprogramming更新于 2025/4/7 12:37:17
要在 R 中将单列 data.table 对象的第一个字母转换为大写，我们可以按照以下步骤操作 −
首先，创建一个带有字符串列的 data.table 对象。
然后，使用 dplyr 包的 sub 函数和 mutate 函数将字符串列的第一个字母转换为大写。
示例
创建 data.table 对象
让我们创建一个 data.table 对象，如下所示 −
library(data.table)
Names<-
sample(c("rahul","rosy","hidayah","seema","john","sarbat","shaun","sam","teena","ila","kunal","sudha","anil","yukti","jerry","tom"),25,replace=TRUE)
DT<-data.table(Names)
DT
输出
执行时，上述脚本生成以下输出(由于随机化，此输出将因您的系统而异) −
Names
1: teena
2: teena
3: seema
4: shaun
5: shaun
6: hidayah
7: rosy
8: kunal
9: tom
10: shaun
11: ila
12: rahul
13: sam
14: rahul
15: teena
16: jerry
17: yukti
18: rosy
19: anil
20: hidayah
21: shaun
22: seema
23: sudha
24: sam
25: anil
Names
将首字母转换为大写
使用 dplyr 包的 sub 函数和 mutate 函数将 Names 列中的首字母转换为大写 −
library(data.table)
Names<-
sample(c("rahul","rosy","hidayah","seema","john","sarbat","shaun","sam","teena","ila","kunal","sudha","anil","yukti","jerry","tom"),25,replace=TRUE)
DT<-data.table(Names)
library(dplyr)
DT %>% mutate(Names=sub("(.)","\U\1",DT$Names,perl=TRUE))
输出
Names
1: Teena
2: Teena
3: Seema
4: Shaun
5: Shaun
6: Hidayah
7: Rosy
8: Kunal
9: Tom
10: Shaun
11: Ila
12: Rahul
13: Sam
14: Rahul
15: Teena
16: Jerry
17: Yukti
18: Rosy
19: Anil
20: Hidayah
21: Shaun
22: Seema
23: Sudha
24: Sam
25: Anil
Names
