如何在R中使用dplyr将单列data.table对象中的首字母转换为大写？

要在R中将单列data.table对象中的首字母转换为大写，我们可以按照以下步骤操作：

• 首先，创建一个包含字符串列的data.table对象。

• 然后，使用dplyr包中的mutate函数和sub函数将字符串列中的首字母转换为大写。

示例

创建data.table对象

让我们创建一个如下所示的data.table对象：

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

执行上述脚本后，将生成以下输出（由于随机化，此输出在您的系统上可能会有所不同）：

    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包中的mutate函数和sub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

Nizamuddin Siddiqui

更新于： 2021年11月10日

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